Brewer’s yeast, which has a very bitter taste, is recovered after being used in the beer-brewing process. Brewer’s yeast can also be grown specifically for harvest as a nutritional supplement. “De-bittered” yeast is also available, though most yeast sold in health food stores that does not taste bitter is not real brewer’s yeast.

Brewer’s yeast is not an essential nutrient, but it can be used as a source of B-complex vitamins and protein. It is by far the best source of chromium, both in terms of quantity and bio-availability.

High cholesterol Type 2 diabetes Diarrhea (infectious)

Side effects have not been reported from the use of brewer’s yeast, although allergies to it exist in some people. It is not related to Candida albicans fungus, which causes yeast infection. Because it contains a highly biologically active form of chromium, supplementation with brewer’s yeast could potentially enhance the effects of drugs for diabetes (e.g., insulin or other blood sugar-lowering agents) and possibly lead to hypoglycemia. Therefore, people with diabetes taking these medications should supplement with chromium or brewer’s yeast only under the supervision of a doctor. Saccharomyces boulardii is registered in Europe under the name Saccharomyces cerevisiae, though the manufacturer states that S. boulardii is not the same as brewer’s yeast (S. cerevisiae). There is a case report of a person with severely impaired immune function who, after receiving treatment with S. boulardii, developed an invasive fungal infection identified as S. cerevisiae. People with severe impairment of the immune system should therefore not take brewer’s yeast or S. boulardii unless supervised by a doctor. Certain medicines may interact with brewer’s yeast. Refer to drug interactions for a list of those medicines.

Brewer’s yeast is often taken as a powder, or as tablets or capsules. High-quality brewer’s yeast powder or flakes contain as much as 60 mcg of chromium per tablespoon (15 grams). When doctors recommend brewer’s yeast, they will often suggest 1–2 tablespoons (15–30 grams) of this high-potency bulk product per day. Remember, if it is not bitter, it is not likely to be real brewer’s yeast and therefore will not contain biologically active chromium. In addition, “primary grown” yeast (i.e., that grown specifically for harvest, as opposed to that recovered in the brewing process) may not contain GTF.

Brewer’s yeast, which has a very bitter taste, is recovered after being used in the beer-brewing process. Brewer’s yeast can also be grown specifically for harvest as a nutritional supplement. “De-bittered” yeast is also available, though most yeast sold in health food stores that does not taste bitter is not real brewer’s yeast.

Brewer’s yeast is not an essential nutrient, but it can be used as a source of B-complex vitamins and protein. It is by far the best source of chromium, both in terms of quantity and bio-availability.

High cholesterol Type 2 diabetes Diarrhea (infectious)

Side effects have not been reported from the use of brewer’s yeast, although allergies to it exist in some people. It is not related to Candida albicans fungus, which causes yeast infection. Because it contains a highly biologically active form of chromium, supplementation with brewer’s yeast could potentially enhance the effects of drugs for diabetes (e.g., insulin or other blood sugar-lowering agents) and possibly lead to hypoglycemia. Therefore, people with diabetes taking these medications should supplement with chromium or brewer’s yeast only under the supervision of a doctor. Saccharomyces boulardii is registered in Europe under the name Saccharomyces cerevisiae, though the manufacturer states that S. boulardii is not the same as brewer’s yeast (S. cerevisiae). There is a case report of a person with severely impaired immune function who, after receiving treatment with S. boulardii, developed an invasive fungal infection identified as S. cerevisiae. People with severe impairment of the immune system should therefore not take brewer’s yeast or S. boulardii unless supervised by a doctor. Certain medicines may interact with brewer’s yeast. Refer to drug interactions for a list of those medicines.

Brewer’s yeast is often taken as a powder, or as tablets or capsules. High-quality brewer’s yeast powder or flakes contain as much as 60 mcg of chromium per tablespoon (15 grams). When doctors recommend brewer’s yeast, they will often suggest 1–2 tablespoons (15–30 grams) of this high-potency bulk product per day. Remember, if it is not bitter, it is not likely to be real brewer’s yeast and therefore will not contain biologically active chromium. In addition, “primary grown” yeast (i.e., that grown specifically for harvest, as opposed to that recovered in the brewing process) may not contain GTF.

Foods of animal origin, such as meat and poultry, fish, eggs, and dairy products, are the richest dietary sources of the essential amino acids. Plant sources of protein are often deficient in one or more essential amino acids. However, these deficiencies can be overcome by consuming a wide variety of plant foods. For example, grains are low in lysine, whereas beans provide an excess of lysine. It was previously believed that, in order for vegetarians to obtain adequate amounts of protein, all of the essential amino acids had to be “balanced” at each meal. For example, a grain and a bean had to be consumed at the same meal. However, more recent research has indicated that, while consuming a proper mix of amino acids is important, it is not necessary to consume them all at the same meal.

The vast majority of Americans eat more than enough protein and also more than enough of each essential amino acid for normal purposes. Dieters, some strict vegetarian body builders, and anyone consuming an inadequate number of calories may not be consuming adequate amounts of amino acids. In these cases, the body will break down the protein in muscle tissue and use those amino acids to meet the needs of more important organs or will simply not build more muscle mass despite increasing exercise.

Angina (carnitine) Bronchitis (N-acetyl cysteine) Chronic obstructive pulmonary disease (N-acetyl cysteine) Cold sores (lysine) Congestive heart failure (propionyl-L-carnitine, taurine) Alzheimer’s disease (acetyl-L-carnitine) Angina (arginine) Athletic performance (creatine) Benign prostatic hyperplasia (alanine, glutamic acid, glycine) Chronic fatigue syndrome (carnitine) Congestive heart failure (arginine) Depression (5-HTP, DLPA, L-phenylalanine, tyrosine) Diabetes (carnitine) Fibromyalgia (5-HTP) High triglycerides (carnitine) HIV support (N-acetyl cysteine) Infertility (male) (arginine, carnitine) Insomnia (5-HTP) Intermittent claudication (carnitine) Liver support (taurine) Migraine headaches (5-HTP) Pain (DPA) Phenylketonuria (tyrosine) Vitiligo (L-phenylalanine) Weight loss and obesity (5-HTP) Alcohol withdrawal (DLPA, glutamine, tyrosine) Athletic performance (arginine/ornithine, carnitine) Diabetes (taurine) Epilepsy (taurine) High blood pressure (arginine, taurine) HIV support (glutamine, methionine) Liver support (methionine) Osteoarthritis (DPA) Peptic ulcer (glutamine) Rheumatoid arthritis (DPA)

Most diets provide more protein than the body needs, causing excess nitrogen to be excreted as urea in urine. The excess nitrogen has been linked in some studies with reduced kidney function in old age. Most, but not all studies have found that when people have impaired kidney function, restricting dietary intake of protein slows the rate of decline of kidney function. Excessive protein intake also can increase excretion of calcium, and some evidence has linked high-protein diets with osteoporosis, particularly regarding animal protein. On the other hand, some protein is needed for bone formation. A double-blind study showed that elderly people whose diets provided slightly less than the recommended amount of protein suffered less bone loss if they consumed an additional 20 grams of protein per day. A doctor can help people assess their protein intake. For the drug interactions safety check, refer to the individual amino acids.

Nutrition experts recommend that protein, as a source of amino acids, should account for 10–12% of the calories in a balanced diet. However, requirements for protein are affected by age, weight, state of health, and other factors. On average, a normal adult requires approximately 0.36 grams of protein per pound of body weight. Using this formula, a 140-pound person would need 50 grams (or less than 2 ounces) of protein per day. An appropriate range of protein intake for healthy adults may be as low as 45–65 grams daily. Some athletes have higher amino acid requirements. Most American adults eat about 100 grams of protein per day, or about twice what their bodies need and at least as much as any athlete requires. Supplements of individual amino acids are recommended by doctors for specific purposes, such as lysine for herpes or phenylalanine for pain.

Dairy products and red meat contain the greatest amounts of BCAAs, although they are present in all protein-containing foods. Whey protein and egg protein supplements are other sources of BCAAs. BCAA supplements provide the amino acids leucine, isoleucine, and valine.

Only a person deficient in protein would become deficient in BCAAs, because most foods that are sources of protein supply BCAAs. Few people in Western societies are protein deficient.

Kidney failure (intravenous BCAAs) Liver cirrhosis Phenylketonuria Athletic performance (for high altitude and extreme temperature only) Hepatic encephalopathy Spinocerebellar degeneration Tardive dyskinesia

Side effects have not been reported with the use of BCAAs. Until more research is conducted, people with ALS should avoid taking supplemental BCAAs. In one study, supplementation with a large amount of BCAAs (60 grams) caused alterations in the blood levels of tryptophan, phenylalanine, and tyrosine. The changes in the blood levels of these amino acids could, in theory, cause depression in susceptible individuals. Until more is known, individuals with a history of depression should consult a doctor before supplementing with BCAAs. People with kidney or liver disease should not consume high amounts of amino acids without consulting their doctor. At the time of writing, there were no well-known drug interactions with branched-chain amino acids.

Most diets provide an adequate amount of BCAAs for most people, which is about 25–65 mg per 2.2 pounds of body weight. Athletes involved in intense training often take 5 grams of leucine, 4 grams of valine, and 2 grams of isoleucine per day to prevent muscle loss and increase muscle gain, though most research does not support this use of BCAAs.

Dairy products and red meat contain the greatest amounts of BCAAs, although they are present in all protein-containing foods. Whey protein and egg protein supplements are other sources of BCAAs. BCAA supplements provide the amino acids leucine, isoleucine, and valine.

Only a person deficient in protein would become deficient in BCAAs, because most foods that are sources of protein supply BCAAs. Few people in Western societies are protein deficient.

Kidney failure (intravenous BCAAs) Liver cirrhosis Phenylketonuria Athletic performance (for high altitude and extreme temperature only) Hepatic encephalopathy Spinocerebellar degeneration Tardive dyskinesia

Side effects have not been reported with the use of BCAAs. Until more research is conducted, people with ALS should avoid taking supplemental BCAAs. In one study, supplementation with a large amount of BCAAs (60 grams) caused alterations in the blood levels of tryptophan, phenylalanine, and tyrosine. The changes in the blood levels of these amino acids could, in theory, cause depression in susceptible individuals. Until more is known, individuals with a history of depression should consult a doctor before supplementing with BCAAs. People with kidney or liver disease should not consume high amounts of amino acids without consulting their doctor. At the time of writing, there were no well-known drug interactions with branched-chain amino acids.

Most diets provide an adequate amount of BCAAs for most people, which is about 25–65 mg per 2.2 pounds of body weight. Athletes involved in intense training often take 5 grams of leucine, 4 grams of valine, and 2 grams of isoleucine per day to prevent muscle loss and increase muscle gain, though most research does not support this use of BCAAs.

Relatively large amounts of isoflavones are present in whole soybeans, roasted soy nuts, tofu, tempeh, soy milk, meat substitutes, soy flour, and some soy protein isolates. In addition, the isoflavones present in soy are available as supplements, in capsules or tablets.

Although deficiencies do not occur, people who do not consume soy foods will not gain the benefits of soy.

High blood pressure High cholesterol Menopause Osteoporosis Premenstrual syndrome (PMS) Vaginitis

Soy products and cooked soybeans are safe at a wide range of intakes. However, a small percentage of people have allergies to soybeans and thus should avoid soy products. Soy isoflavones have been reported to reduce thyroid function in some people. A preliminary trial of soy supplementation among healthy Japanese, found that 30 grams (about one ounce) per day of soybeans for three months, led to a slight reduction in the hormone that stimulates the thyroid gland. Some participants complained of malaise, constipation, sleepiness, and even goiter. These symptoms resolved within a month of discontinuing soy supplements. However, a variety of soy products have been shown to either cause an increase in thyroid function or produce no change in thyroid function. The clinical importance of interactions between soy and thyroid function remains unclear. However, in infants with congenital hypothyroidism, soy formula must not be added, nor removed from the diet, without consultation with a physician, because ingestion of soy may interfere with the absorption of thyroid medication. Most research, including animal studies, report anticancer effects of soy extracts, though occasional animal studies have reported cancer-enhancing effects. The findings of several recent studies suggest that consuming soy might, under some circumstances, increase the risk of breast cancer. When ovaries have been removed from animals a situation related to the condition of women who have had a total hysterectomy dietary genistein has been reported to increase the proliferation of breast cancer cells. When pregnant rats were given genistein injections, their female offspring were reported to be at greater risk of breast cancer. Although premenopausal women have shown decreases in estrogen levels in response to soy, pro-estrogenic effects have also been reported. When pre-menopausal women were given soy isoflavones, an increase in breast secretions resulted an effect thought to elevate the risk of breast cancer. In yet another trial, healthy breast cells from women previously given soy supplements containing isoflavones showed an increase in proliferation rates an effect that might also increase the risk of breast cancer. Of 154 healthy postmenopausal women who received 150 mg of soy isoflavones per day for five years, 3.9% developed an abnormal proliferation of the tissue that lines the uterus (endometrial hyperplasia). In contrast, none of 144 women who received a placebo developed uterine hyperplasia. Although no case of uterine cancer was diagnosed during the study, endometrial hyperplasia is a potential forerunner of uterine cancer. The amount of isoflavones used in this study is two to three times as much as that used in many other studies. Nevertheless, the possibility exists that long-term use of isoflavones could cause uterine hyperplasia, and women taking isoflavones should be monitored appropriately by their doctor. Soy contains a compound called phytic acid, which can interfere with mineral absorption. Certain medicines may interact with soy. Refer to drug interactions for a list of those medicines.

The ideal intake of soy is not known. Researchers suggest the equivalent of one serving of soy foods per day supports good health, and the benefits increase as soy intake increases. Societies in which large amounts of soy are consumed ingest between 50 and 100 mg per day of soy isoflavones. The cholesterol-lowering effects of soy have been observed at amounts as low as 20 grams of soy protein per day, if it replaces animal protein in the diet.