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Nutr Metab Cardiovasc Dis. And even more remarkable for it to be awarded to someone who has been dead for so many years. Nonsmokers should be advised not to use e-cigarettes. Body aches, fatigue, tiredness, nausea, no appetite that would last about days.. Neurological changes, such as numbness and tingling in the hands and feet, can also occur [ 5 , 31 ]. Differentiation between primary and secondary hypertension in children using ambulatory blood pressure monitoring.
Routine supplementation with antioxidants, such as vitamins E and C and carotene, is not advised because of lack of evidence of efficacy and concern related to long-term safety. There is insufficient evidence to support the routine use of micro-nutrients such as chromium, magnesium, and vitamin D to improve glycemic control in people with diabetes.
There currently exists insufficient evidence of benefit from vitamin or mineral supplementation in people with or without diabetes in the absence of an underlying deficiency 3 , , Because uncontrolled diabetes is often associated with micronutrient deficiencies , people with diabetes should be aware of the importance of acquiring daily vitamin and mineral requirements from natural food sources and a balanced diet 3.
For select groups of individuals such as the elderly, pregnant or lactating women, vegetarians, and those on calorie-restricted diets, a multivitamin supplement may be necessary While there has been significant interest in antioxidant supplementation as a treatment for diabetes, current evidence not only demonstrates a lack of benefit with respect to glycemic control and progression of complications, but also provides evidence of potential harm of vitamin E, carotene, and other antioxidant supplements — A systematic review on the effect of chromium supplementation on glucose metabolism and lipids concluded that larger effects were more commonly observed in poor-quality studies and that evidence is limited by poor study quality and heterogeneity in methodology and results Evidence from clinical studies evaluating magnesium , and vitamin D — supplementation to improve glycemic control in people with diabetes is likewise conflicting.
A systematic review evaluating the effects of cinnamon in people with diabetes concluded there is currently insufficient evidence to support its use, and there is a lack of compelling evidence for the use of other herbal products for the improvement of glycemic control in people with diabetes It is important to consider that herbal products are not standardized and vary in the content of active ingredients and may have the potential to interact with other medications If adults with diabetes choose to drink alcohol, they should be advised to do so in moderation one drink per day or less for adult women and two drinks per day or less for adult men.
Alcohol consumption may place people with diabetes at increased risk for delayed hypoglycemia, especially if taking insulin or insulin secretagogues.
Education and awareness regarding the recognition and management of delayed hypoglycemia is warranted. Moderate alcohol intake may also convey cardiovascular risk reduction and mortality benefits in people with diabetes — , with the type of alcohol consumed not influencing these beneficial effects , Accordingly, the recommendations for alcohol consumption for people with diabetes are the same as for the general population.
Adults with diabetes choosing to consume alcohol should limit their intake to one serving or less per day for women and two servings or less per day for men One alcohol-containing beverage is defined as 12 oz beer, 5 oz wine, or 1.
Abstention from alcohol should be advised, however, for people with a history of alcohol abuse or dependence, women during pregnancy, and people with medical conditions such as liver disease, pancreatitis, advanced neuropathy, or severe hypertriglyceridemia 3.
Despite the potential glycemic and cardiovascular benefits of moderate alcohol consumption, use may place people with diabetes at increased risk for delayed hypoglycemia. This is particularly true in those using insulin or insulin secretagogue therapies.
Consuming alcohol with food can minimize the risk of nocturnal hypoglycemia 3 , — Individuals with diabetes should receive education regarding the recognition and management of delayed hypoglycemia and the potential need for more frequent self-monitoring of blood glucose after consuming alcoholic beverages. For individuals with both diabetes and hypertension, further reduction in sodium intake should be individualized. Limited studies have been published on sodium reduction in people with diabetes.
A Cochrane review of RCTs found that decreasing sodium intake reduces blood pressure in those with diabetes Likewise, a small study in people with type 2 diabetes showed that following the DASH diet and reducing sodium intake to about 2, mg led to improvements in blood pressure and other measures on cardiovascular risk factors Incrementally lower sodium intakes i.
Additionally, an IOM report suggests there is no evidence on health outcomes to treat certain population subgroups—which includes individuals with diabetes—differently than the general U. When individualizing sodium intake recommendations, consideration must also be given to issues such as the palatability, availability, and additional cost of specialty low sodium products and the difficulty in achieving both low sodium recommendations and a nutritionally adequate diet given these limitations The food industry can play a major role in lowering sodium content of foods to help people meet sodium recommendations , A wide range of diabetes meal planning approaches or eating patterns have been shown to be clinically effective, with many including a reduced energy intake component.
There is not one ideal percentage of calories from carbohydrates, protein, or fat that is optimal for all people with diabetes. If the individual would like to try a different eating pattern, this should also be supported by the health care team.
Various behavior change theories and strategies can be used to tailor nutrition interventions to help the client achieve specific health and quality-of-life outcomes Multiple meal planning approaches and eating patterns can be effective for achieving metabolic goals.
This may need to be adjusted over time based on changes in life circumstances, preferences, and disease course. A summary of key topics for nutrition education can be found in Table 4. The evidence presented in this position statement concurs with the review previously published by Wheeler et al. Evaluating nutrition evidence is complex given that multiple dietary factors influence glycemic control and CVD risk factors, and the influence of a combination of factors can be substantial.
Based on a review of the evidence, it is clear that gaps in the literature continue to exist and further research on nutrition and eating patterns is needed in individuals with type 1 and type 2 diabetes.
The basis for the beneficial effects of the Mediterranean-style eating pattern and approaches to translation of the Mediterranean-style eating pattern into diverse populations. The development of standardized definitions for high— and low—glycemic index diets and implementation of these definitions in long-term studies to further evaluate their impact on glycemic control. The development of standardized definitions for low- to moderate-carbohydrate diets and determining long-term sustainability.
Whether NNSs, when used to replace caloric sweeteners, are useful in reducing caloric and carbohydrate intake. The impact of key nutrients on cardiovascular risk, such as saturated fat, cholesterol, and sodium in individuals with both type 1 and type 2 diabetes. Importantly, research needs to move away from just evaluating the impact of individual nutrients on glycemic control and cardiovascular risk.
More research on eating patterns, unrestricted and restricted energy diets, and diverse populations is needed to evaluate their long-term health benefits in individuals with diabetes.
Individuals eat nutrients from foods and within the context of mixed meals, and nutrient intakes are intercorrelated, so overall eating patterns must be studied to fully understand how these eating patterns impact glycemic control 88 , Eating patterns are selected by individuals based on more than the healthfulness of food and food availability; tradition, cultural food systems, health beliefs, and economics are also important Studies on gene-diet interactions will also be important, as well as studies on potential epigenetic effects that depend on nutrients to moderate gene expression.
Given the benefits of both nutrition therapy and MNT for individuals with diabetes, it is also important to study systematic processes within the context of health care delivery that encourage more individuals with diabetes to receive nutrition therapy initially, upon diagnosis, and long term.
Further research is also needed on the best tools and strategies for educating individuals with diabetes e. This research should include multiple settings that can impact food choices for individuals with diabetes, such as where they live, work, learn, and play.
Individuals with diabetes spend the majority of their time outside health care settings so more research on how public health, the health care system, and the community can support individuals with diabetes in their efforts to achieve healthful eating is needed. There is no standard meal plan or eating pattern that works universally for all people with diabetes 1.
Nutrition interventions should emphasize a variety of minimally processed nutrient-dense foods in appropriate portion sizes as part of a healthful eating pattern and provide the individual with diabetes with practical tools for day-to-day food plan and behavior change that can be maintained over the long term.
This position statement was written at the request of the ADA Executive Committee, which has approved the final document. The process involved extensive literature review, one face-to-face meeting of the entire writing group, one subgroup writing meeting, numerous teleconferences, and multiple revisions via e-mail communications.
The authors are indebted to Sue Kirkman, MD, for her guidance and support during this process. The two face-to-face meetings and the travel of the writing group and teleconference calls were supported by the ADA. The authors also gratefully acknowledge the following experts who provided critical review of a draft of this statement: During the past 12 months, the following relationships with companies whose products or services directly relate to the subject matter in this document are declared: No other potential conflicts of interest relevant to this article were reported.
All the named writing group authors contributed substantially to the document including researching data, contributing to discussions, writing and reviewing text, and editing the manuscript. All authors supplied detailed input and approved the final version. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail.
We do not capture any email address. Skip to main content. Diabetes Care Jan; 37 Supplement 1: View inline View popup. Table 1 Nutrition therapy recommendations. Achieve and maintain body weight goals.
Delay or prevent complications of diabetes. Diabetes nutrition therapy Ideally, the individual with diabetes should be referred to a registered dietitian RD or a similarly credentialed nutrition professional if outside of the U. View inline View popup Download powerpoint. Effectiveness of Nutrition Therapy Nutrition therapy is recommended for all people with type 1 and type 2 diabetes as an effective component of the over all treatment plan.
A Individuals who have diabetes should receive individualized MNT as needed to achieve treatment goals, preferably provided by an RD familiar with the components of diabetes MNT.
A For individuals with type 1 diabetes, participation in an intensive flexible insulin therapy education program using the carbohydrate counting meal planning approach can result in improved glycemic control.
A For individuals using fixed daily insulin doses, consistent carbohydrate intake with respect to time and amount can result in improved glycemic control and reduce the risk for hypoglycemia. B A simple diabetes meal planning approach such as portion control or healthful food choices may be better suited to individuals with type 2 diabetes identified with health and numeracy literacy concerns. B Because diabetes nutrition therapy can result in cost savings B and improved outcomes such as reduction in A1C A , nutrition therapy should be adequately reimbursed by insurance and other payers.
E The common coexistence of hyperlipidemia and hypertension in people with diabetes requires monitoring of metabolic parameters e. Energy Balance For overweight or obese adults with type 2 diabetes, reducing energy intake while maintaining a healthful eating pattern is recommended to promote weight loss. A More than three out of every four adults with diabetes are at least overweight 17 , and nearly half of individuals with diabetes are obese Optimal Mix of Macronutrients Evidence suggests that there is not an ideal percentage of calories from carbohydrate, protein, and fat for all people with diabetes B ; therefore, macronutrient distribution should be based on individualized assessment of current eating patterns, preferences, and metabolic goals.
E Although numerous studies have attempted to identify the optimal mix of macronutrients for the meal plans of people with diabetes, a systematic review 88 found that there is no ideal mix that applies broadly and that macronutrient proportions should be individualized. Eating Patterns A variety of eating patterns combinations of different foods or food groups are acceptable for the management of diabetes.
E Eating patterns, also called dietary patterns, is a term used to describe combinations of different foods or food groups that characterize relationships between nutrition and health promotion and disease prevention Table 3 Reviewed eating patterns. Individual macronutrients Carbohydrates Evidence is inconclusive for an ideal amount of carbohydrate intake for people with diabetes.
C The amount of carbohydrates and available insulin may be the most important factor influencing glycemic response after eating and should be considered when developing the eating plan.
A Monitoring carbohydrate intake, whether by carbohydrate counting or experience-based estimation, remains a key strategy in achieving glycemic control. B For good health, carbohydrate intake from vegetables, fruits, whole grains, legumes, and dairy products should be advised over intake from other carbohydrate sources, especially those that contain added fats, sugars, or sodium. B Evidence is insufficient to support one specific amount of carbohydrate intake for all people with diabetes.
Quality of carbohydrates Glycemic Index and Glycemic Load Substituting low—glycemic load foods for higher—glycemic load foods may modestly improve glycemic control. C The ADA recognizes that education about glycemic index and glycemic load occurs during the development of individualized eating plans for people with diabetes. Dietary Fiber and Whole Grains People with diabetes should consume at least the amount of fiber and whole grains recommended for the general public.
C Intake of dietary fiber is associated with lower all-cause mortality , in people with diabetes. Resistant starch and fructans Resistant starch is defined as starch physically enclosed within intact cell structures as in some legumes, starch granules as in raw potato, and retrograde amylose from plants modified by plant breeding to increase amylose content.
Substitution of Sucrose for Starch While substituting sucrose-containing foods for isocaloric amounts of other carbohydrates may have similar blood glucose effects, consumption should be minimized to avoid displacing nutrient-dense food choices.
A Sucrose is a disaccharide made of glucose and fructose. C People with diabetes should limit or avoid intake of sugar-sweetened beverages SSBs from any caloric sweetener including high-fructose corn syrup and sucrose to reduce risk for weight gain and worsening of cardiometabolic risk profile.
B Fructose is a monosaccharide found naturally in fruits. Nonnutritive Sweeteners and Hypocaloric Sweeteners Use of nonnutritive sweeteners NNSs has the potential to reduce overall calorie and carbohydrate intake if substituted for caloric sweeteners without compensation by intake of additional calories from other food sources. Protein For people with diabetes and no evidence of diabetic kidney disease, evidence is inconclusive to recommend an ideal amount of protein intake for optimizing glycemic control or improving one or more CVD risk measures; therefore, goals should be individualized.
C For people with diabetes and diabetic kidney disease either micro- or macroalbuminuria , reducing the amount of dietary protein below the usual intake is not recommended because it does not alter glycemic measures, cardiovascular risk measures, or the course of glomerular filtration rate GFR decline. A In individuals with type 2 diabetes, ingested protein appears to increase insulin response without increasing plasma glucose concentrations.
Total Fat Evidence is inconclusive for an ideal amount of total fat intake for people with diabetes; therefore, goals should be individualized. B Currently, insufficient data exist to determine a defined level of total energy intake from fat at which risk of inadequacy or prevention of chronic disease occurs, so there is no adequate intake or recommended daily allowance for total fat B Evidence from large prospective cohort studies, clinical trials, and a systematic review of RCTs indicate that high-MUFA diets are associated with improved glycemic control and improved CVD risk or risk factors 70 , — Omega-3 Fatty Acids Evidence does not support recommending omega-3 EPA and DHA supplements for people with diabetes for the prevention or treatment of cardiovascular events.
A As recommended for the general public, an increase in foods containing long-chain omega-3 fatty acids EPA and DHA from fatty fish and omega-3 linolenic acid ALA is recommended for individuals with diabetes because of their beneficial effects on lipoproteins, prevention of heart disease, and associations with positive health outcomes in observational studies. B The recommendation for the general public to eat fish particularly fatty fish at least two times two servings per week is also appropriate for people with diabetes.
B The ADA systematic review identified seven RCTs and one single-arm study — using omega-3 fatty acid supplements and one cohort study on whole-food omega-3 intake. Saturated Fat, Dietary Cholesterol, and Trans Fat The amount of dietary saturated fat, cholesterol, and trans fat recommended for people with diabetes is the same as that recommended for the general population.
C Few research studies have explored the relationship between the amount of SFA in the diet and glycemic control and CVD risk in people with diabetes. Plant Stanols and Sterols Individuals with diabetes and dyslipi-demia may be able to modestly reduce total and LDL cholesterol by consuming 1.
C Plant sterol and stanol esters block the intestinal absorption of dietary and biliary cholesterol 3. Micronutrients and Herbal Supplements There is no clear evidence of benefit from vitamin or mineral supplementation in people with diabetes who do not have underlying deficiencies.
C Routine supplementation with antioxidants, such as vitamins E and C and carotene, is not advised because of lack of evidence of efficacy and concern related to long-term safety. A There is insufficient evidence to support the routine use of micro-nutrients such as chromium, magnesium, and vitamin D to improve glycemic control in people with diabetes. E There currently exists insufficient evidence of benefit from vitamin or mineral supplementation in people with or without diabetes in the absence of an underlying deficiency 3 , , Alcohol If adults with diabetes choose to drink alcohol, they should be advised to do so in moderation one drink per day or less for adult women and two drinks per day or less for adult men.
E Alcohol consumption may place people with diabetes at increased risk for delayed hypoglycemia, especially if taking insulin or insulin secretagogues. B For individuals with both diabetes and hypertension, further reduction in sodium intake should be individualized.
B Limited studies have been published on sodium reduction in people with diabetes. Clinical priorities for nutrition management for all people with diabetes A wide range of diabetes meal planning approaches or eating patterns have been shown to be clinically effective, with many including a reduced energy intake component.
Table 4 Summary of priority topics. Future research directions The evidence presented in this position statement concurs with the review previously published by Wheeler et al. For example, future studies should address: The relationships between eating patterns and disease in diverse populations. Intake of SFA and its relationship to insulin resistance. In summary There is no standard meal plan or eating pattern that works universally for all people with diabetes 1.
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A simple meal plan emphasizing healthy food choices is as effective as an exchange-based meal plan for urban African Americans with type 2 diabetes. Development of a new method for simple dietary education in elderly patients with diabetes mellitus.
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Diabet Med ; Effects of carbohydrate counting on glucose control and quality of life over 24 weeks in adult patients with type 1 diabetes on continuous subcutaneous insulin infusion: A brief structured education programme enhances self-care practices and improves glycaemic control in Malaysians with poorly controlled diabetes.
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Effects of a Mediterranean-style diet on the need for antihyperglycemic drug therapy in patients with newly diagnosed type 2 diabetes: Ann Intern Med ; The effect of high-protein, low-carbohydrate diets in the treatment of type 2 diabetes: Table 1 lists the current RDAs for selenium in mcg.
For infants from birth to 12 months, the FNB established an AI for selenium that is equivalent to the mean intake of selenium in healthy, breastfed infants. Seafoods and organ meats are the richest food sources of selenium [ 1 ].
Other sources include muscle meats, cereals and other grains, and dairy products. The amount of selenium in drinking water is not nutritionally significant in most geographic regions [ 2 , 6 ]. The major food sources of selenium in the American diet are breads, grains, meat, poultry, fish, and eggs [ 7 ].
The amount of selenium in a given type of plant-based food depends on the amount of selenium in the soil and several other factors, such as soil pH, amount of organic matter in the soil, and whether the selenium is in a form that is amenable to plant uptake [ 2 , 6 , 8 , 9 ].
As a result, selenium concentrations in plant-based foods vary widely by geographic location [ 1 , 2 ]. For example, according to the U.
The selenium content of soil affects the amounts of selenium in the plants that animals eat, so the quantities of selenium in animal products also vary [ 2 , 5 ]. However, selenium concentration in soil has a smaller effect on selenium levels in animal products than in plant-based foods because animals maintain predictable tissue concentrations of selenium through homeostatic mechanisms. Furthermore, formulated livestock feeds generally contain the same levels of selenium.
DVs were developed by the U. Food and Drug Administration FDA to help consumers compare the nutrient contents of products within the context of a total diet. The DV for selenium is 70 mcg for adults and children aged 4 and older. Few studies have compared the relative absorption and bioavailability of different forms of selenium.
Selenium bioavailability, based on urinary excretion, was greatest for selenomethionine and lowest for selenite. However, supplementation with any of these forms only affected plasma selenium levels and not glutathione peroxidase activity or selenoprotein P concentration, confirming that study participants were selenium replete before they began taking selenium supplements. Most Americans consume adequate amounts of selenium.
Adult men have higher daily intakes mcg from foods and mcg from foods and supplements than adult women 93 mcg from foods and mcg from foods and supplements. Men have slightly higher serum selenium levels than women, and whites have higher levels than African Americans [ ]. Selenium intakes and serum concentrations in the United States and Canada vary somewhat by region because of differences in the amounts of selenium in soil and in local foods consumed [ 6 , 19 ].
For example, concentrations are higher in residents of the Midwestern and Western United States than in the South and Northeast [ 18 , 19 ]. The extensive transport of food typically allows people living in low-selenium areas to obtain sufficient amounts of selenium [ 6 ]. Selenium deficiency produces biochemical changes that might predispose people who experience additional stresses to develop certain illnesses [ 6 ].
For example, selenium deficiency in combination with a second stress possibly a viral infection leads to Keshan disease, a cardiomyopathy that occurred in parts of China prior to a government-sponsored selenium supplementation program that began in the s [ 2 , 5 , 8 , 20 ]. Selenium deficiency is also associated with male infertility and might play a role in Kashin-Beck disease, a type of osteoarthritis that occurs in certain low-selenium areas of China, Tibet, and Siberia [ 1 , 2 , 5 , 6 , 8 , 21 ].
Selenium deficiency could exacerbate iodine deficiency, potentially increasing the risk of cretinism in infants [ 2 , 5 ]. Selenium deficiency is very rare in the United States and Canada, and selenium deficiency in isolation rarely causes overt illness [ 6 ]. The following groups are among those most likely to have inadequate intakes of selenium. However, people in some other countries whose diet consists primarily of vegetables grown in low-selenium areas are at risk of deficiency [ 6 ].
The lowest selenium intakes in the world are in certain parts of China, where large proportions of the population have a primarily vegetarian diet and soil selenium levels are very low [ 5 ]. Average selenium intakes are also low in some European countries, especially among populations consuming vegan diets [ 5 , 9 , 22 ].
Although intakes in New Zealand were low in the past, they rose after the country increased its importation of high-selenium wheat [ 9 ]. Selenium levels are significantly lower in patients undergoing long-term hemodialysis than in healthy individuals.
Hemodialysis removes some selenium from the blood [ 23 ]. In addition, hemodialysis patients are at risk of low dietary selenium intakes due to anorexia resulting from uremia and dietary restrictions. Although selenium supplementation increases blood levels in hemodialysis patients, more evidence is needed to determine whether supplements have beneficial clinical effects in these individuals.
Selenium levels are often low in people living with HIV, possibly because of inadequate intakes especially in developing countries , excessive losses due to diarrhea, and malabsorption [ 2 , 24 ]. Observational studies have found an association between lower selenium concentrations in people with HIV and an increased risk of cardiomyopathy, death, and, in pregnant women, HIV transmission to offspring and early death of offspring [ ].
Some randomized clinical trials of selenium supplementation in adults with HIV have found that selenium supplementation can reduce the risk of hospitalization and prevent increases of HIV-1 viral load; preventing HIV-1 viral load progression can lead to increases in numbers of CD4 cells, a type of white blood cell that fights infection [ 30 , 31 ].
However, one trial showed that selenium supplementation in pregnant women can prevent early death in infants but has no effects on maternal viral load or CD4 counts [ 32 , 33 ]. This section focuses on four diseases and disorders in which selenium might play a role: Because of its effects on DNA repair, apoptosis, and the endocrine and immune systems as well as other mechanisms, including its antioxidant properties, selenium might play a role in the prevention of cancer [ 2 , 9 , 34 , 35 ].
Epidemiological studies have suggested an inverse association between selenium status and the risk of colorectal, prostate, lung, bladder, skin, esophageal, and gastric cancers [ 36 ].
The authors found no association between selenium intake and risk of breast cancer. A meta-analysis of 20 epidemiologic studies showed a potential inverse association between toenail, serum, and plasma selenium levels and prostate cancer risk [ 37 ]. Randomized controlled trials of selenium supplementation for cancer prevention have yielded conflicting results. The authors of a Cochrane review concluded, based on nine randomized clinical trials, that selenium might help prevent gastrointestinal cancers but noted that these results need to be confirmed in more appropriately designed randomized clinical trials [ 38 ].
A secondary analysis of the double-blind, randomized, controlled Nutritional Prevention of Cancer Trial in 1, U. In , the FDA allowed a qualified health claim on foods and dietary supplements containing selenium to state that while "some scientific evidence suggests that consumption of selenium may reduce the risk of certain forms of cancer FDA has determined that this evidence is limited and not conclusive" [ 42 ].
More research is needed to confirm the relationship between selenium concentrations and cancer risk and to determine whether selenium supplements can help prevent any form of cancer. Selenoproteins help prevent the oxidative modification of lipids, reducing inflammation and preventing platelets from aggregating [ 9 ]. For these reasons, experts have suggested that selenium supplements could reduce the risk of cardiovascular disease or deaths associated with cardiovascular disease.
The epidemiological data on the role of selenium in cardiovascular disease have yielded conflicting conclusions. Some observational studies have found an inverse association between serum selenium concentrations and risk of hypertension or coronary heart disease. A meta-analysis of 25 observational studies found that people with lower selenium concentrations had a higher risk of coronary heart disease [ 43 ].
However, other observational studies failed to find statistically significant links between selenium concentrations and risk of heart disease or cardiac death, or they found that higher selenium concentrations are associated with an increased risk of cardiovascular disease [ ]. Several clinical trials have examined whether selenium supplementation reduces the risk of cardiovascular disease.
In one randomized, placebo-controlled study, for example, healthy adults aged 60 to 74 years with a mean baseline plasma selenium concentration of 9. A review of trials of selenium-only supplementation for the primary prevention of cardiovascular disease found no statistically significant effects of selenium on fatal and nonfatal cardiovascular events [ 51 ].
Almost all of the subjects in these clinical trials were well-nourished male adults in the United States. The limited clinical-trial evidence to date does not support the use of selenium supplements for preventing heart disease, particularly in healthy people who already obtain sufficient selenium from food. Additional clinical trials are needed to better understand the contributions of selenium from food and dietary supplements to cardiovascular health.
Serum selenium concentrations decline with age. The results of observational studies are mixed [ 54 ]. In two large studies, participants with lower plasma selenium levels at baseline were more likely to experience cognitive decline over time, although whether the participants in these studies were selenium deficient is not clear [ 52 , 55 , 56 ].
An analysis of NHANES data on 4, elderly people in the United States found no association between serum selenium levels which ranged from lower than Researchers have evaluated whether taking an antioxidant supplement containing selenium reduces the risk of cognitive impairment in elderly people.
MAX study on 4, participants aged 45 to 60 years in France found that, compared with placebo, daily supplementation with mg ascorbic acid, 30 mg vitamin E, 6 mg beta-carotene, mcg selenium, and 20 mg zinc for 8 years was associated with higher episodic memory and semantic fluency test scores 6 years after the study ended [ 58 ].
More evidence is required to determine whether selenium supplements might help prevent or treat cognitive decline in elderly people. Selenium concentration is higher in the thyroid gland than in any other organ in the body, and, like iodine, selenium has important functions in thyroid hormone synthesis and metabolism.
Fermentable fibers are consumed by the microbiota within the large intestines, mildly increasing fecal bulk and producing short-chain fatty acids as byproducts with wide-ranging physiological activities discussion below. Resistant starch , inulin , fructooligosaccharide and galactooligosaccharide are dietary fibers which are fully fermented.
These include insoluble as well as soluble fibers. This fermentation influences the expression of many genes within the large intestine,  which affect digestive function and lipid and glucose metabolism, as well as the immune system, inflammation and more. Dietary fibers can change the nature of the contents of the gastrointestinal tract and can change how other nutrients and chemicals are absorbed through bulking and viscosity.
Insoluble fiber is associated with reduced risk of diabetes, but the mechanism by which this is achieved is unknown. Not yet formally proposed as an essential macronutrient , dietary fiber has importance in the diet, with regulatory authorities in many developed countries recommending increases in fiber intake. Dietary fiber has distinct physicochemical properties.
Most semi-solid foods, fiber and fat are a combination of gel matrices which are hydrated or collapsed with microstructural elements, globules, solutions or encapsulating walls. Fresh fruit and vegetables are cellular materials. Micelles are colloid-sized clusters of molecules which form in conditions as those above, similar to the critical micelle concentration of detergents. The multiple physical phases in the intestinal tract slow the rate of absorption compared to that of the suspension solvent alone.
Adding viscous polysaccharides to carbohydrate meals can reduce post-prandial blood glucose concentrations. Wheat and maize but not oats modify glucose absorption, the rate being dependent upon the particle size. The reduction in absorption rate with guar gum may be due to the increased resistance by viscous solutions to the convective flows created by intestinal contractions.
Dietary fiber interacts with pancreatic and enteric enzymes and their substrates. Human pancreatic enzyme activity is reduced when incubated with most fiber sources. Fiber may affect amylase activity and hence the rate of hydrolysis of starch.
The more viscous polysaccharides extend the mouth-to- cecum transit time; guar, tragacanth and pectin being slower than wheat bran. The substrates utilized by the cecum have either passed along the entire intestine or are biliary excretion products. The effects of dietary fiber in the colon are on. Enlargement of the cecum is a common finding when some dietary fibers are fed and this is now believed to be normal physiological adjustment. Such an increase may be due to a number of factors, prolonged cecal residence of the fiber, increased bacterial mass, or increased bacterial end-products.
Some non-absorbed carbohydrates, e. Almost all of these short-chain fatty acids will be absorbed from the colon. This means that fecal short-chain fatty acid estimations do not reflect cecal and colonic fermentation, only the efficiency of absorption, the ability of the fiber residue to sequestrate short-chain fatty acids, and the continued fermentation of fiber around the colon, which presumably will continue until the substrate is exhausted.
The production of short-chain fatty acids has several possible actions on the gut mucosa. All of the short-chain fatty acids are readily absorbed by the colonic mucosa, but only acetic acid reaches the systemic circulation in appreciable amounts. Butyric acid appears to be used as a fuel by the colonic mucosa as the preferred energy source for colonic cells.
Dietary fiber may act on each phase of ingestion, digestion, absorption and excretion to affect cholesterol metabolism,  such as the following:.
An important action of some fibers is to reduce the reabsorption of bile acids in the ileum and hence the amount and type of bile acid and fats reaching the colon. A reduction in the reabsorption of bile acid from the ileum has several direct effects.
The fibers that are most effective in influencing sterol metabolism e. It is therefore unlikely that the reduction in body cholesterol is due to adsorption to this fermented fiber in the colon. Feces consist of a plasticine-like material, made up of water, bacteria, lipids, sterols, mucus and fiber.
Wheat bran is minimally fermented and binds water and when added to the diet increases fecal weight in a predictable linear manner and decreases intestinal transit time. The particle size of the fiber is all-important, coarse wheat bran being more effective than fine wheat bran. The greater the water-holding capacity of the bran, the greater the effect on fecal weight. The fermentation of some fibers results in an increase in the bacterial content and possibly fecal weight.
Research has shown that fiber may benefit health in several different ways. Lignin and probably related materials that are resistant to enzymatic degradation, diminish the nutritional value of foods. Fiber does not bind to minerals and vitamins and therefore does not restrict their absorption, but rather evidence exists that fermentable fiber sources improve absorption of minerals, especially calcium. The analytic cohort consisted of , men and , women aged 50—71 years.
Diet was assessed with a self-administered food-frequency questionnaire at baseline in —; 2, incident colorectal cancer cases were identified during five years of follow-up. The result was that total fiber intake was not associated with colorectal cancer. Although many researchers believe that dietary fiber intake reduces risk of colon cancer, one study conducted by researchers at the Harvard School of Medicine of over 88, women did not show a statistically significant relationship between higher fiber consumption and lower rates of colorectal cancer or adenomas.
Dietary fiber has many functions in diet, one of which may be to aid in energy intake control and reduced risk for development of obesity. The role of dietary fiber in energy intake regulation and obesity development is related to its unique physical and chemical properties that aid in early signals of satiation and enhanced or prolonged signals of satiety.
Early signals of satiation may be induced through cephalic- and gastric-phase responses related to the bulking effects of dietary fiber on energy density and palatability, whereas the viscosity-producing effects of certain fibers may enhance satiety through intestinal-phase events related to modified gastrointestinal function and subsequent delay in fat absorption. In general, fiber-rich diets, whether achieved through fiber supplementation or incorporation of high fiber foods into meals, have a reduced energy density compared with high fat diets.
There are also indications that women may be more sensitive to dietary manipulation with fiber than men. The relationship of body weight status and fiber effect on energy intake suggests that obese individuals may be more likely to reduce food intake with dietary fiber inclusion. Current recommendations from the United States National Academy of Sciences , Institute of Medicine , state that for Adequate Intake, adult men ages 14—50 consume 38 grams of dietary fiber per day, men 51 and older 30 grams, women ages 19—50 to consume 25 grams per day, women 51 and older 21 grams.
No guidelines have yet been established for the elderly or very ill. Patients with current constipation , vomiting , and abdominal pain should see a physician.
Certain bulking agents are not commonly recommended with the prescription of opioids because the slow transit time mixed with larger stools may lead to severe constipation, pain, or obstruction. As of , the British Nutrition Foundation has recommended a minimum fiber intake of 30 grams per day for healthy adults. The FDA classifies which ingredients qualify as being "fiber", and requires for product labeling that a physiological benefit is gained by adding the fiber ingredient.
Other examples of bulking fiber sources used in functional foods and supplements include cellulose , guar gum and xanthan gum. Other examples of fermentable fiber sources from plant foods or biotechnology used in functional foods and supplements include resistant starch , inulin , fructans , fructooligosaccharides, oligo- or polysaccharides, and resistant dextrins , which may be partially or fully fermented.
Consistent intake of fermentable fiber may reduce the risk of chronic diseases. In , the British Nutrition Foundation issued a statement to define dietary fiber more concisely and list the potential health benefits established to date, while increasing its recommended daily intake to 30 grams for healthy adults. The use of certain analytical methods to quantify dietary fiber by nature of its indigestibility results in many other indigestible components being isolated along with the carbohydrate components of dietary fiber.
These components include resistant starches and oligosaccharides along with other substances that exist within the plant cell structure and contribute to the material that passes through the digestive tract. Such components are likely to have physiological effects. Diets naturally high in fiber can be considered to bring about several main physiological consequences: Fiber is defined by its physiological impact, with many heterogenous types of fibers.
Some fibers may primarily impact one of these benefits i. Defining fiber physiologically allows recognition of indigestible carbohydrates with structures and physiological properties similar to those of naturally occurring dietary fibers. The American Association of Cereal Chemists has defined soluble fiber this way: As an example of fermentation, shorter-chain carbohydrates a type of fiber found in legumes cannot be digested, but are changed via fermentation in the colon into short-chain fatty acids and gases which are typically expelled as flatulence.
According to a journal article,  fiber compounds with partial or low fermentability include:. When fermentable fiber is fermented, short-chain fatty acids SCFA are produced. SCFAs are involved in numerous physiological processes promoting health, including: SCFAs that are absorbed by the colonic mucosa pass through the colonic wall into the portal circulation supplying the liver , and the liver transports them into the general circulatory system.
Overall, SCFAs affect major regulatory systems, such as blood glucose and lipid levels, the colonic environment, and intestinal immune functions. The major SCFAs in humans are butyrate , propionate , and acetate , where butyrate is the major energy source for colonocytes , propionate is destined for uptake by the liver, and acetate enters the peripheral circulation to be metabolized by peripheral tissues. The FDA statement template for making this claim is: Soluble fiber from foods such as [name of soluble fiber source, and, if desired, name of food product], as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.
The allowed label may state that diets low in saturated fat and cholesterol and that include soluble fiber from certain of the above foods "may" or "might" reduce the risk of heart disease. Soluble fiber from consuming grains is included in other allowed health claims for lowering risk of some types of cancer and heart disease by consuming fruit and vegetables 21 CFR In December , FDA approved a qualified health claim that consuming resistant starch from high- amylose corn may reduce the risk of type 2 diabetes due to its effect of increasing insulin sensitivity.