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.14Niacinamide 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
Dosage/Timing
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
- Whitney E, Rolfes S. Understanding Nutrition, Ninth Edition, Belmont, CA: Wadsworth/Thomson Learning; 2002.
- Whitney E, Rolfes S. Understanding Nutrition, Ninth Edition, Belmont, CA: Wadsworth/Thomson Learning; 2002.
- Depeint F, Bruce WR, Shangari N, Mehta R, O'Brien PJ. Mitochondrial function and toxicity: role of the B vitamin family on mitochondrial energy metabolism. Chem Biol Interact 2006;163(1-2):94-112.
- Shane B. Folic acid, vitamin B-12, and vitamin B-6. In: Stipanuk M, ed. Biochemical and Physiological Aspects of Human Nutrition. Philadelphia: W.B. Saunders Co.; 2000:483-518.
- McCormick DB. Vitamin B6. In: Bowman BA, Russell RM, eds. Present Knowledge in Nutrition. Vol. I. Washington, D.C.: International Life Sciences Institute; 2006:269–277.
- Manore MM. Effect of physical activity on thiamine, riboflavin, and vitamin B-6 requirements. Am J Clin Nutr 2000 Aug;72(2 Suppl):598S–606S.
- Woolf K, Manore MM. B-vitamins and exercise: does exercise alter requirements? Int J Sport Nutr Exerc Metab 2006 Oct;16(5):453-84.
- Manore MM. Effect of physical activity on thiamine, riboflavin, and vitamin B-6 requirements. Am J Clin Nutr 2000 Aug;72(2 Suppl):598S-606S.
- Whitney E, Rolfes S. Understanding Nutrition, Ninth Edition, Belmont, CA: Wadsworth/Thomson Learning; 2002.
- Sauberlich HE. Implications of nutritional status on human biochemistry, physiology, and health. Clin Biochem 1984; 17(2):132–42.
- Bondarev GI, Martinchik AN, Khotimchenko SA, et al. [Correlation of the actual vitamin B1, B2 and B6 consumption with the biochemical indices of their body allowance] Korreliativnaia vzaimosviaz' fakticheskogo potrebleniia vitaminov B1, B2 i B6 s biokhimicheskimi pokazateliami obespechennosti imi organizma. Vopr Pitan 1986; (2):34–7.
- Bogdanov NG, Bondarev GI, Piatnitskaia IN, et al. [Vitamin status of diamond cutters] Vitaminnyi status rabochikn, zaniatykh promyshlennoi obrabotkoi almazov. Vopr Pitan 1984; (2):28–31.
- Vinogradov VV, Tarasov IuA, Tishin VS, et al. [Thiamine prevention of the corticosteroid reaction after surgery] Optimizatsiia tiaminom korticosteroidnoi reaktsii pri khirurgicheskikh vmeshatel'stvakh. Probl Endokrinol 1981;27(3):11–6.
- Kutsky R, Handbook of Vitamins and Hormones. New York: Van Nostrand Reinhold Company; 1973:208.
- Mukherjee SK; Adams JD Jr. The effects of aging and neurodegeneration on apoptosis-associated DNA fragmentation and the benefits of nicotinamide. Mol Chem Neuropathol 1997; 32(1-3):59–74.
- Meerson FZ, Manukhina EB, Dosmagambetova RS. [Disorders of contractile function and adrenoreactivity of the portal vein in emotionally-painful stress and experimental myocardial infarct and their prevention by means of membrane protectors] Narusheniia sokratitel'noi funktsii i adrenoreaktivnosti vorotnoi veny pri emotsional'no-bolevom stresse i eksperimental'no-bolevom stresse i eksperimental'nom infarkte miokarda i ikh preduprezhdenie s pomoshch'iu membranoprotektorov. Kardiologiia 1984; 24(4):104–8.
- Meerson FZ, Pshennikova MG, Rysmendiev AZh, Vorontsova EIa. [Prevention of stress disorders of myocardial contractile function using membrane protectors] Preduprezhdenie stressornykh narushenii sokratitel'noi funktsii miokarda s pomoshch'iu membranoprotektorov. Kardiologiia1983;23(7):86-90.
- Baldewicz T, Goodkin K, Feaster DJ, et al. Plasma pyridoxine deficiency is related to increased psychological distress in recently bereaved homosexual men. Psychosom Med 1998; 60(3):297–308.
- Teggin AF, van Niekerk JP. Manifestations and management of stress. S Afr Med J 1981;59(21):751–2.
- Whitney E, Rolfes S. Understanding Nutrition, Ninth Edition, Belmont, CA: Wadsworth/Thomson Learning; 2002.
- Whitney E, Rolfes S. Understanding Nutrition, Ninth Edition, Belmont, CA: Wadsworth/Thomson Learning; 2002.
- Bjorkegren K, Svardsudd. Elevated serum levels of methylmalonic acid and homocysteine in elderly people. A population-based intervention study. J Intern Med 1999; 246(3):317–24.
- Rasmussen K, Moller J, Lyngbak M. Within-person variation of plasma homocysteine and effects of posture and tourniquet application. Clin Chem 1999; 45(10):1850–5.
- Kunz K, Petitjean P, Lisri M, et al. Cardiovascular morbidity and endothelial dysfunction in chronic haemodialysis patients: Is homocyst(e)ine the missing link? Nephrol Dial Transplant1999; 14(8):1934–42.
- Alpert MA, Homocysteine, atherosclerosis, and thrombosis. South Med J 1999; 92(9):858–65.
- Bellamy MF, McDowell IF, Ramsey MW, et al. Oral folate enhances endothelial function in hyperhomocysteinaemic subjects. Eur J Clin Invest 1999; 29(8):659–62.
- Woodside JV, Young IS, Yarnell JWG, et al. Antioxidants, but not B-group vitamins increase the resistance to low-density lipoprotein to oxidation: a randomized, factorial design, placebo-controlled trial. Atherosclerosis 1999; 144(2):419–27.
- Bronstrup A, Hages M, Pietrzik K. Lowering of homocysteine concentrations in elderly men and women. Int J Vitam Nutr Res 1999; 69(3):187–93.
- Suliman ME, Divino Filho JC, Barany P, et al. Effects of high-dose folic acid and pyridoxine on plasma and erythrocyte sulfur amino acids in hemodialysis patients. J Am Soc Nephrol 1999; 10(6):1287–96.
- Mansoor MA, Kristensen O, Hervig T, et al. Plasma total homocysteine response to oral doses of folic acid and pyridoxine hydrochlpride (vitamin B6) in healthy individuals. Oral doses of vitamin B6 reduce concentration of serum folate. Scand J Clin Lab Invest 1999; 59(2):139–46.
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, vitamin B-6, Folate, Vitamin B-12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press, 1998.
- CDC (Centers for Disease Control). Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. MMWR 1992; 41 (No. RR-14).
- Moshfegh AJ, Tippett KS, Borrud LG, Perloff BP. Food and Nutrient Intakes by Individuals in the United States, by Sex and Age, 1994-96. Agriculture Research Service; http://www.nalusda.gov/ttic/tektran/data/000009/29/0000092962.html.
- Werback M. The Great American Nutrient Gap. Nutrition Science News 1998.
- Lewis DP, Van Dyke DC, Willhite LA, et al. Phenytoin-folic acid interaction. Ann Pharmacother 1995;29:726–35.
- Para-aminobenzoic acid monograph. Natural Medicines Comprehensive Database. 1995-2009 Therapeutic Research Faculty. Retrieved April 23, 2009 from http://www.naturaldatabase.com/(S(sujm1emnfd4v5uzxvt05q555))/nd/Search.aspx?rn=4&cs=&s=ND&pt=100&id=1004&fs=ND&searchid=14605586.