Vitamins are organic components in food that are needed in very small amounts for growth and for maintaining good health. Pauling believed that vitamins and supplements had one property that made them cure-alls, a property that continues to be hawked on everything from ketchup to pomegranate juice and that rivals words like natural and organic for sales impact: antioxidant.
Given the consistency of these results — large effects in observational data, nothing in randomized trials — it’s worth asking what might be going on to better understand whether or not other relationships we see in observational data on vitamins are likely to be replicated in randomized trials.
Vitamins can be separated into two groups; water soluble vitamins (Vitamin C, B Vitamins) and fat soluble vitamins (Vitamins A, D, E, K). Water soluble vitamins are needed in regular small amounts and are unlikely to reach toxic levels in the blood as they are excreted in urine.
If you want to take a mult-vitamin supplement specifically aimed at helping to reduce PMS symptoms, ensure that it includes vitamins A, C, D, and E, in addition to B vitamins, and the minerals phosphorous, potassium, calcium, magnesium, manganese, pantothenic acid, iron, and zinc.
A four-year study conducted by researchers from Harvard Medical School and other prominent universities found that individuals with retinitis pigmentosa who took daily supplements of vitamin A (15,000 IU) and lutein (12 mg) had a slower loss of peripheral vision than those who did not take the combined supplements.