The safety of vitamin D, vitamin C, niacin, and thiamine for adults is extremely well understood. Supplements of these four essential nutrients have been around since the 1940’s. All four are sold without child proof caps because there is no lethal dose. Regular use in high doses causes side effects. Millions of adults have used all four of these supplements in doses 10 to 100 times the RDA for extended periods of time. A small fraction of these have become ill and provided reliable and reproducible information of their experiences to their physicians. These reports are collected by the Food and Nutrition Board and converted into safe upper limit doses (UL’s). The Food and Nutrition Board specifies that the RDA’s will protect 97-98% of the population from deficiency diseases. I could not find what statistics are used for the UL’s and will assume a similar reasoning. The UL’s are probably doses that 97-98% of the population can consume on a daily basis without side effects.

I argued in a recent column that if vitamin dosing was managed the same way as drug dosing there would be no difference between the UL’s and the RDA’s. Read more here. Like drugs, the benefits of vitamins are well understood to increase with increasing dose. Everyone should take supplements of the most important vitamins to ensure that they receive close to the UL – the maximum dose that can be taken without risk.

An important task of vitamin C, vitamin D, niacin, and thiamine is to catalyze the growth and development of an egg and sperm into a healthy adult. Read more here and here. Many functions of these vitamins are unique to growth and development. As a result, children are at much higher risk of deficiency than adults. Children are not at higher risk for catastrophic deficiency disease. They are at higher risk for loss of potential. Subtle vitamin deficiency can cause a loss of height, intelligence, muscle strength, endurance, toughness…. When thinking about nutrition, we must think about our children first. Just as importantly, when thinking about our children, we have to think about safety first. This is why I’m unhappy about the way the Food and Nutrition Board has handled the UL’s for children.

Vitamin C, vitamin D, thiamine, and niacin are the only components of the human diet that cause deficiency diseases so widespread and dreaded that they earned names. Vitamin C prevents scurvy. Vitamin D prevents rickets. Niacin prevents pellegra. Thiamine prevents beriberi. I recommend that mothers take the UL’s of these vitamins before conception and switch to the lower doses in pregnancy vitamins when actually pregnant. Once the baby is born, I recommend they return to the UL’s of these four vitamins and breast feed the baby. Once the baby is weaned, I recommend taking vitamin C, vitamin D, niacin, and thiamine at the adult UL’s. Specifically, thiamine has no UL’s because there are no statistically significant reports of side effects at any dose. Since it is so safe, I recommend children take two 100 mg tablets per day (once in the morning and once in the evening). Vitamin D can be obtained from the sun in doses above the UL for supplements with no known risk of side effects. Parents should see to it that their children get regular mid-day sun exposure from the moment they are born. It goes without saying that parents and children must manage the risks of sun burn. So for two of the four vitamins I recommend for children – thiamin and vitamin D – the safety of my advice is unquestioned.

My problem with the Food and Nutrition Board is limited to vitamin C and niacin. I recommend that weaned children start out with 2000 mg/day of vitamin C (the adult UL) twice a day (vitamin C is purged from the body in less than 12 hours). I recommend that weaned children take a 125 mg tablet of time release niacin twice per week (this averages 35 mg/day, very close to the adult UL of 30 mg/day). For both these vitamins, the Food and Nutrition Board has conservatively decided to scale the UL roughly with body weight. Very few children take vitamin supplements. All children taking vitamins are closely supervised and are at a much lower risk of overdose. As a result, vitamin overdoses among children are almost unknown. I’m very sceptical that the Food and Nutrition Board has collected a statistically insignificant number of reliable reports. I do not believe that the Food and Nutrition Board is using real overdose incidents to set the UL’s for children. I believe they are using a paradigm used for drugs. The assumption is that optimal doses are proportional to body weight, and do not change with growth and development. This is a very bad assumption for vitamins and children. Again – children need more vitamins because in addition to maintaining the health of existing cells, vitamins are need to catalyze growth and development. Vitamins are essential tools nature uses to convert egg and sperm into strong adult minds and bodies.

After intensively studying the safety and effectiveness of vitamins, I arrived at a working hypothesis that optimal vitamin doses are nearly independent of age from birth through adulthood. This hypothesis served me well with my own children, and the children in my small clinical practice. If anything, after more than 15 years of practice, I’m concluding that the UL’s probably increase with decreasing age. I can only think of one incident of a minor side effect with a child less than 5 years old. I can think of dozens of incidents with older children and teenagers.

The UL’s are invaluable information. I have high confidence in the adult UL’s set by the Food and Nutrition Board. I have little confidence in the rest. When UL’s for children as a function of age are set based on statistically significant, reliable information, I will respect them. The data is the data. In the meantime, I strongly recommend that parents and pediatricians consider supplementing weaned children with vitamin C and niacin at the adult UL’s.

If your children are in excellent health, this may be a difficult decision although even this I find a bit illogical. The risk being run is of experiencing fully reversible side effects while the risk of not supplementing is reduced height, intelligence, strength, endurance….. If your child is not in excellent health ( just a single cavity is a sign of sub-optimal health, and vitamins have proven ability to prevent cavities) then there is much to gain and little to lose.