What are they?
The water-soluble B vitamins are collectively referred to as "B-Complex." They include thiamine (B1), riboflavin (B2), niacin or niacinamide (B3), pyridoxine (B6), folic acid, vitamin B12 (cyanocobalamin or methylcobalamin), biotin and pantothenic acid (B5). In addition, choline, inositol and PABA (paraaminobenzoic acid) are compounds that are not technically B vitamins but which have related functions and so are often included with B-Complex products.

B vitamins are found in whole unprocessed foods. Processed carbohydrates such as sugar and white flour tend to have lower B vitamins than their unprocessed counterparts. B vitamins are particularly concentrated in meat such as turkey and tuna, in liver and meat products. Other good sources for B vitamins include kombucha, whole grains, potatoes, bananas, lentils, chili peppers, tempeh, beans, nutritional yeast, brewer's yeast, and molasses.1

What Does It Do?
Each of the B vitamins has their own functions to serve in the body, but in general they may be considered to play a role in energy metabolism and helping to promote homeostasis when the body is under stress. The use of the entire B-Complex is recommended since the individual B vitamins affect one another's absorption, metabolism, and excretion.2

B-Complex And Energy
Each of the B vitamins is converted into coenzymes in the body. These B vitamin coenzymes are involved, directly or indirectly in energy metabolism. Some are facilitators of the energy-releasing reactions themselves within the mitochondria; others help build new cells to deliver the oxygen and nutrients that permit the energy pathways to run. Thiamin is essential for the oxidative decarboxylation of the multienzyme branched-chain ketoacid dehydrogenase complexes of the citric acid cycle. Riboflavin is required for the flavoenzymes of the respiratory chain, while NADH is synthesized from niacin and is required to supply protons for oxidative phosphorylation. Pantothenic acid is required for coenzyme A formation and is also essential for alphaketoglutarate and pyruvate dehydrogenase complexes as well as fatty acid oxidation. Biotin is the coenzyme of decarboxylases required for gluconeogenesis and fatty acid oxidation.3 Folic acid and choline are believed to be central methyl donors required for mitochondrial protein and nucleic acid synthesis through their active forms. Vitamin B12 is necessary for the biochemical reaction that plays an important role in the production of energy from fats and proteins.4 One of vitamin B6's coenzyme forms, pyridoxal 5'-phosphate, works with glycogen phosphorylase, an enzyme that catalyzes the release of glucose from stored glycogen.5

Active individuals with poor or marginal nutritional status for a B vitamin may have decreased ability to perform exercise at high intensities. Exercise stresses metabolic pathways that depend on thiamine, riboflavin, and vitamin B6. Consequently, the requirements for these vitamins may be increased in athletes and active individuals.6 In fact, exercise could increase the need for these micronutrients in several ways: through decreased absorption of the nutrients; by increased turnover, metabolism, or loss of the nutrients; through biochemical adaptation as a result of training that increases nutrient needs; by an increase in mitochondrial enzymes that require the nutrients; or through an increased need for the nutrients for tissue maintenance and repair. Other research7 also suggests that exercise may increase the requirements for riboflavin and vitamin B6, and possibly for folic acid and vitamin B12. Biochemical evidence of deficiencies in some of these vitamins in active individuals has been reported, including riboflavin and vitamin B6.8 Exercise appears to decrease nutrient status even further in active individuals with preexisting marginal vitamin intakes or marginal body stores. Thus, active individuals who restrict their energy intake or make poor dietary choices are at greatest risk for poor B vitamin status, and should consider supplementing with B-complex vitamins.

B-Complex And Stress
The B-complex vitamins are intimately involved in the function of the nervous system,9 and so can play a role in helping to counter some of the negative effects of stress. In fact, the ability of humans to respond to stresses can be influenced by nutritional status—including the status of key B vitamins.10 In one study, vitamin B1 (thiamine) and vitamin B6 (pyridoxine) together were found to be especially necessary for workers whose activity is associated with nervous-emotional stress.11 Similar results were seen in a previous study.12

Research on individual B vitamins has also revealed important roles where stress and the nervous system are concerned. For example, vitamin B1 was found to reduce the effects of catabolic (i.e., breaking down tissues) stress hormones, which resulted from surgery. It also protected the adrenal glands (the "stress glands") from functional exhaustion.13 Pantothenic acid is intimately involved in adrenal function, and the production of adrenal hormones associated with stress.14 Niacinamide has been found to reduce certain neurological damage caused by oxidative stress,15 as well as to prevent heart disturbances that resulted from emotional-painful stress.16,17 Vitamin B6 deficiency has been found to be related to increased psychological distress in recently bereaved men;18 and supplementation with vitamin B6 is suggested as part of an overall program for stress.19 Vitamin B12 is also necessary for nervous system functioning, and a deficiency can lead to fatigue and degeneration of peripheral nerves.20 Finally, the concurrent use of B vitamins (i.e., B-complex) together is recommended since they affect one another's absorption, metabolism, and excretion.21

B-Complex And Homocysteine
A substantial body of scientific evidence suggests that generous intakes of three B vitamins may help improve cardiovascular health in the United States. The particular B vitamins involved are folic acid, vitamin B6 and vitamin B12. Research indicates these vitamins help promote healthy levels of homocysteine, the amino acid byproduct of metabolism. This is important since high homocysteine levels are a risk factor for cardiovascular disease, on par with high cholesterol levels. Numerous studies indicate that homocysteine levels can be normalized, using vitamin B6, vitamin B12 and folic acid; either individually or in combination.22,23,24,25,26,27,28,29,30

Folic Acid And Preventing Birth Defects
One of the most exciting scientific developments in the past several decades is the finding that folic acid plays a critical role in protecting against some serious birth defects, including neural tube defects, when taken by women of childbearing age before and during pregnancy. The Food and Nutrition Board of the Institute of Medicine recognized these findings when it issued new dietary recommendations for the B vitamins in 1998 recommending, "that women capable of becoming pregnant use supplements, fortified foods, or both in addition to consuming food folate from a varied diet." The Food and Nutrition Board added, "At this time the evidence for a protective effect from folate supplements is much stronger than that for food folate."31 The Centers for Disease Control and Prevention (CDC) started even earlier by issuing a public health recommendation in 1992 urging all women of childbearing age to get 400 mcg of folic acid daily to help neural tube defects.32

Who should use it?
Anyone and everyone should be using the B-complex vitamins. This is especially true of people who need energy to work out in a gym, or participate in a sport. B vitamins are a fundamental part of basic nutritional needs, and research has shown Americans don't always consume sufficient amount of some B vitamins.33 For example, in a large national survey, 71 percent of males and 90 percent of females consumed less than the recommended daily allowance for vitamin B6.34

The two products that typically contain the B-complex vitamins are B-complex supplements and multivitamins. In the case of many low-potency, drug store brand type multivitamins, Daily Value levels of the individual B vitamins are used; for example, 1.5 mg of vitamin B1 and 1.7 mg of vitamin B2. Sometimes these levels are doubled, so now there is 3 mg of vitamin B1, etc. While these levels have value and are likely sufficient for preventing a nutrient deficiency disease, experience and empirical evidence suggests they wouldn't be likely to have much of an effect on noticeably increasing energy levels or helping to reduce symptoms of stress. Rather, increasing the dose so that there is at least 10–15 mg (or more) of each B vitamin is more realistic for purposes of energy and stress. For individuals who are under significant amounts of stress and/or who have higher energy needs, higher doses of each vitamin might even be used.

Since B vitamins are commonly used for energy and stress, it makes sense to use them in the earlier part of the day rather than in the evening. In fact, taking them in the evening may cause an increase in energy before bedtime, making it more difficult to fall asleep. Ideally, B vitamins should be taken with breakfast or lunch. It is important to take them with food for two reasons. First, B vitamins work with food and cellular enzymes to help produce ATP, the primary cellular energy molecule. Second, taking B vitamins on an empty stomach may cause some stomach upset (e.g., mild nausea).

Also, keep in mind that when first taking B vitamins it may take a few weeks until you notice a substantial increase in energy. The reason for this is that your body needs time to produce more cellular enzymes to work with the B-vitamin coenzymes.

Adverse Reactions/Interactions
Folic acid may reduce serum levels of phenytoin in some patients, and may increase seizure frequency,35 so patients concurrently taking medications such as Cerebyx, Luminal, Dilantin, and Mysoline should be carefully monitored. A characteristic flushing reaction can occur with doses of niacin as low as 30 mg/day (but not with niacinamide), but occurs more commonly with the larger doses commonly used for treatment of hyperlipidemia. PABA inhibits the antimicrobial activity of sulfonamide antibiotics, and might inhibit the antibacterial effects of dapsone; avoid concurrent use.36

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Gene Bruno, MS, MHS

Gene Bruno is the Dean of Academics and Professor of Dietary Supplement Science for Huntington College of Health Sciences (a nationally accredited distance learning college offering diplomas and degrees in nutrition and other health science related subjects. Gene has two undergraduate Diplomas in Nutrition, a Bachelor’s in Nutrition, a Master’s in Nutrition, a Graduate Diploma in Herbal Medicine, and a Master’s in Herbal Medicine. As a 32 year veteran of the Dietary Supplement industry, Gene has educated and trained natural product retailers and health care professionals, has researched and formulated natural products for dozens of dietary supplement companies, and has written articles on nutrition, herbal medicine, nutraceuticals and integrative health issues for trade, consumer magazines, and peer-reviewed publications. Gene's latest book, A Guide to Complimentary Treatments for Diabetes, is available on Amazon.com, and other fine retailers.