Brewer's yeast is made from a one-celled fungus called Saccharomyces cerevisiae and is used to make beer. It also can be grown specifically to make nutritional supplements. Brewer's yeast is a rich source of minerals -- particularly chromium, an essential trace mineral that helps the body maintain normal blood sugar levels; selenium; protein; and the B-complex vitamins. It tastes bitter and should not be confused with baker's yeast, nutritional yeast, or torula yeast; all those types of yeast are low in chromium. Brewer's yeast has been used for years as a nutritional supplement.

General

Brewer's yeast is often used as a source of B-complex vitamins, chromium, and selenium. The B-complex vitamins in brewer's yeast include B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B9 (folic acid), and H or B7 (biotin). These vitamins help break down carbohydrates, fats, and proteins, which provide the body with energy. They also support the nervous system, help maintain the muscles used for digestion, and keep skin, hair, eyes, mouth, and liver healthy. However, brewer's yeast does not contain vitamin B12, an essential vitamin found in meat and dairy products; vegetarians sometimes take brewer's yeast mistakenly believing that it provides B12, which can be lacking in their diet.

Diabetes

Some studies suggest that chromium supplements may help people with diabetes control blood sugar levels. People with diabetes either do not produce enough insulin -- a hormone needed to convert sugar, starches and other food into energy needed for daily life -- or cannot use the insulin that their bodies produce. Chromium may reduce blood sugar levels as well, improving glucose tolerance (reducing the amount of insulin needed). Because brewer's yeast is a rich source of chromium, scientists think it may be effective in treating high blood sugar.

High Cholesterol

A few studies suggest that brewer's yeast may help lower LDL ("bad") cholesterol levels in the blood and raise HDL ("good") cholesterol levels. Researchers aren't sure whether that is due to the chromium in brewer's yeast or another substance, and not all studies have found the same benefit.

Weight Loss

Although some studies suggest that chromium may help reduce body fat, the amount of fat lost is not much compared to what can be lost with exercise and a well-balanced diet. However, brewer's yeast is used as a protein supplement and energy booster, so it may help with weight management.

Other Uses

At least one study has found that brewer's yeast may improve acne. Another linked it to a reduced risk of a second skin cancer.

Brewer's yeast is available in powder, flakes, tablet, and liquid forms.

Pediatric

Brewer's yeast has not been studied in children, so it is not recommended for pediatric use.

Adult

• 1 - 2 Tbsp per day; may be added to food or dissolved in juice or water.

Because supplements may have side effects or interact with medications, you should take them only under the supervision of your health care provider.

Side effects from brewer's yeast are generally mild and may include gas.

People who are susceptible to yeast infections or are allergic to yeast should avoid brewer's yeast.

People with diabetes should talk to their doctor before taking brewer's yeast, as it could interact with medication for diabetes and cause hypoglycemia. (See "Possible Interactions" sections.)

If you are currently being treated with any of the following medications, you should not use brewer's yeast without first talking to your health care provider.

Monoamine Oxidase Inhibitors (MAOIs) -- Brewer's yeast contains a large amount of tyramine, a substance that can interact with MAOIs and cause a hypertensive crisis. A hypertensive crisis is characterized by a rapid and dangerous rise in blood pressure that can cause heart attack or stroke. MAOIs are used to treat depression and include:

• Phenelzine (Nardil)
• Tranylcypromine (Parnate)
• Selegiline (Ensam, Eldepryl)
• Isocarboxazid (Marplan)

Meperidine (Demerol) -- As with MAOI antidepressants, brewer's yeast may also lead to hypertensive crisis if taken with Demerol, a narcotic medication used to relieve pain.

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