
Background:
There are eight B vitamins generally known as thiamin (B-1), riboflavin (B-2), niacin (B-3), pantothenic acid (B-5), pyridoxine (B-6), biotin (B-7), folic acid (folate) (B-9), and cyanocobalamin (B-12). Like most vitamins, B vitamins are essential — your body needs them but cannot make them; you must get them from your diet or from supplements.
Each B vitamin is associated with a variety of functions, many of which relate to turning food into energy and other needed substances. Folate, for example, is important in reducing birth defects of the spinal cord and is, therefore, a critical ingredient in prenatal vitamins. But at a high dosage, folic acid may increase the risk of certain cancers. Niacin, when taken in very high doses, can improve cholesterol levels but can also cause side-effects and toxicity. Several (B-6, B-12, and folate) have been shown to reduce elevated homocysteine levels -- a risk factor for cardiovascular disease, although studies have not shown this combination to reduce cardiovascular risk itself
Previous reviews by ConsumerLab.com have uncovered problems with the B vitamin content of several supplements. Neither the U.S. government nor any agency is responsible for routinely testing B vitamin products or other dietary supplements for their contents or quality
• 5-Hour Energy (Berry) contained only 75.5% of its claimed folic acid, although it did contain its claimed amounts of niacin, B-6, and B-12. The amount of B-6 and B-12 in this product is many times higher than the RDAs for these ingredients, although not exceeding tolerable upper limits for those vitamins. For young adults, the RDA for B-6 is 1.3 mg and for B-12 is 2.4 mcg, while the suggested serving (one bottle) provides 40 mg of B-6 (3,100% of the RDA) and 500 mcg of B-12 (20,800% of the RDA).
5-Hour Energy lists among its ingredients an "energy blend" that includes caffeine. The label notes that the amount of caffeine is comparable to that in a cup of "leading premium coffee." ConsumerLab.com found the 2 fluid ounce bottle to contain 207 mg of caffeine. However, this is 15% higher than what you would get from a "short" cup (8 fluid ounces) of a premium coffee such as Starbucks, which Starbucks claims to have 180 mg of caffeine (Starbucks.com 2010).
• Stacker 2 6-Hour Power Shot contained just 40.4% of its claimed folic acid. It provided the same high levels of B-6 (40 mg) and B-12 (500 mcg) as 5-Hour Energy. Also, like 5-Hour Energy, 6-Hour Power Shot also lists among its ingredients an "energy blend" that includes caffeine. The label notes that the amount of caffeine is comparable to that in a cup of "brewed coffee". ConsumerLab.com found the 2 fluid ounce bottle to contain 156 mg of caffeine. However, this is 64% higher than what you would get from a cup (8 fluid ounces) of brewed coffee based on measurements by the USDA of coffee brewed at home and from fast food restaurants (USDA National Nutrient Database 2010)).
Unlike 5-Hour Energy which directs the user not to exceed 2 bottles per day, 6-Hour Power Shot only cautions not to exceed 1 shot every six hours -- which means taking as much as four bottles per day. Be aware that taking 3 or 4 bottles of 6-Hour Power can result in exceeding the Upper Tolerable Intake Levels for several B vitamins (niacin, vitamin B-6, and folic acid), creating a risk of toxicity. Intake exceeding 1,000 mg of folic acid, for example, may increase the risk of precancerous tumors becoming malignant: If 6-Hour Power contained the amount of folic acid that it claimed, 3 to 4 bottles would provide 1,200 mg to 1,600 mg of folic acid, exceeding the ULs. It would be prudent to limit intake of 6-Hour Power to under 2.5 bottles per day. B Complexes:
Supplements containing more than one B vitamin are widely sold. However, two common reasons for buying these complexes are not well supported by scientific evidence.
Our Recommendations:
• AVOID! AVOID AVOID!
• Try to avoid taking too much of any B vitamin. Check the ULs listed above and, if you need to take a product with vitamins exceeding the ULs, do so under a physician's supervision and with awareness of potential side effects. For example, a recent large study of diabetes patients with advanced nephropathy (kidney disease) given high-dose B vitamins (folic acid - 2.5 mg, B-6 - 25 mg, and B-12 - 1 mg daily) showed a worsening of kidney function and doubling of the risk of myocardial infarction (MI), stroke, and death in the B-vitamin group compared to the placebo group. The study was designed with the expectation that the vitamins would have the opposite effect because of the ability of B vitamins to lower homocysteine levels, which did decrease. (House, JAMA 2010)
• Be aware that certain B vitamins can interact with other drugs and supplements as noted above.
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