Next up in our vitamin march is Vitamin B2, also known as riboflavin. Riboflavin in our diet mostly comes from meat, dairy products, eggs, green leafy vegetables, almonds, or mushrooms. Yeast, liver, and kidney are particularly rich in riboflavin. Also, like thiamine riboflavin is found in cereal grains such as wheat and rice but again is mostly in the outer portion or the germ and therefore much of it is lost in processed grains (yet again, it is important to eat whole grains when possible). Riboflavin is easily destroyed by UV light so some recommend buying dairy products in containers that do not allow light to pass through.
This is the vitamin that gives your urine that neon yellow appearance if you take B vitamin supplements or a multivitamin with high doses of riboflavin. Riboflavin is important for energy metabolism and is required in the processing of other vitamins including Vitamin A, Vitamin B6, and Vitamin B3 and the absorption and processing of iron. It helps maintain normal adrenal gland and nervous system function.
The recommended daily allowance of riboflavin is 1.2 mg per day. However, the recommended daily allowance of Vitamin B2 (and for all the other vitamins) given the data we have should be seen more as a bare minimum for survival and not as a goal for intake per day. Like the other B vitamins, riboflavin is a water-soluble vitamin, so it is not stored by the body in significant amounts and if intake is not sufficient deficiency will occur quickly (within days or weeks). However, this water-soluble quality also makes riboflavin very safe to take in higher quantities as the excess is easily excreted by the body in the urine. However very high doses possibly may increase the risk for kidney stones and may cause some skin irritation.
deficiency of riboflavin (a condition known as ariboflavinosis) usually presents with weakness, fatigue, dry cracked lips, inflammation of the mouth and tongue, sore throat and mouth ulcers. Dry scaly skin, irritation of the eyes, and anemia may also occur.
Some recognized uses of riboflavin are supplementation to infants receiving UV light for neonatal jaundice (the yellowing of the skin due to bilirubin from broken down red blood cells that is treated with the famous bili blanket) because the UV light breaks down the riboflavin in the baby’s blood. It is also used in conjunction with UV light that is used to sterilize pathogens in blood products that are donated and applied to the cornea before UV treatments for Keratoconus (a thinning and mis-shaping of the cornea into a cone shape).
There was some excitement when it was found that pregnant women who were riboflavin deficient had a nearly 5 times increased risk for preeclampsia. Preeclampsia is a condition in pregnant women of unknown cause where they develop protein in the urine and elevated blood pressure in the later stages of their pregnancy. The blood pressure can get dangerously high and it can progress to eclampsia which is when those with preeclampsia then have seizures. The hopes were that riboflavin supplemenation would prevent and treat this. However this was studied by Neurgebauer et. al in good placebo controlled trial in 450 pregnant woman, and they found no decrease in risk of preeclampsia with riboflavin supplementation.
Multiple studies have shown a decrease risk for cataracts in those that eat higher amounts of riboflavin. This would make sense as well as deficiency is known to cause eye irritation. However a good randomized placebo controlled trial of riboflavin supplementation to prevent cataracts has yet to be done despite this being one of the most common conditions of old age and cataract surgery is the most common surgery done on the elderly in America. Over 20 million Americans have catract and it affects 50% of those over the age of 80. The surgery for cataract is performed on approximately 3 million Americans per year and costs Medicare an estimated 3.4 Billion dollars per year.
Multiple smalls studies have also shown a benefit to migraine headache sufferers with riboflavin. When taken together the strength of these studies is quite strong and they were placebo controlled. There is also good science behind why this may work. Riboflavin helps with energy metabolism in the mitochondria (a part of cells that is devoted to energy production) and some studies have shown that oxygen metabolism by mitochondria may play a role in migraines. Interestingly the maximum benefit seemed to not be achieved until about 3 months of treatment. The reason for this is unclear.
I had also noted the symptoms of riboflavin deficiency are almost identical to a condition called mucositis that we see in many cancer patient’s receiving chemotherapy or radiation. Mucositis causes severe mouth, tongue and throat irritation and ulcers, sometimes to the point patients cannot eat. Sure enough, when I went to the literature there was evidence that riboflavin supplementation may prevent this. However it is still in the preclinical phase and trials on actualy patients have yet to be done. Vitamin E has also been shown to be effective. Topical Vitamin E seems to be more effective than Vitamin E pills.
Given the data I feel riboflavin needs to be tested in a large randomized study to see if it can alleviate mucositis. This is a debilitating condition that causes severe pain to cancer patient undergoing so much pain and suffering already. We also need a large randomized trial to definitively assess the role riboflavin supplementation may play in cataract prevention.
However, I feel it would be appropriate to start migraine sufferers and elderly on B complex supplementation with the data we have given riboflavin’s almost complete lack of side effects and risk for toxicity. However in cancer patients undergoing chemotherapy and radiation with mucositis this would have to be looked at more closely as the supplementation’s effect on their chemotherapy and cancer is still not known. However topical Vitamin E seems very promising and giving it topically dramatically decreases any risk for interaction with chemotherapy or effect on the cancer.
Riboflavin and preeclampsia – Neugebauer J, Zanre Y, Wacker J. Riboflavin supplementation and preeclampsia. Int J Gynaecol Obstet
Riboflavin and cataracts–