Getting nutrients from food is ideal. Most multivitamins are synthetic and studies show they either provide no benefit and may cause harm in certain cases. The synergistic effect of eating whole food where the vitamin are found together is lost in supplements. For example extra virgin cod liver oil has both vitamin A and D. Liver is the best form of bioavailable vitamin A. If too much is consumed it could be toxic however nature made this food is difficult to overdose on. The form of vitamin A found in supplements is beta carotene. There is an association with lung cancer and cardiovascular disease when over-supplemented which is more common than we think.
One nutrient to supplement and why?
Vitamin A is important for vision, cell growth and nutrient assimilation as well as having anti-oxidant actions. It supports full term pregnancy and proper fetal development. Retinol is pre-formed vitamin A and is found only in liver and eggs. Its precursor beta carotene requires consuming 20-50 times the amount and isn’t always bioavailable. In fact 50% of the population has trouble making this conversion. We can test serum levels of vitamin A and what we see is that beta carotene does not raise vitamin A levels whereas retinol does. Serum levels go down only after the liver stores have been depleted which is likely to happen in vegetarian/vegans eventually. The body compensates for inadequate intake by going to its reserves but once serum levels drop there is a serious problem that will have health consequences. Optimal levels are 1.4 to 2.13 ug. I encourage people to eat a varied diet. Periods of being a vegetarian can be good but any restricted diet over a long period is not recommended.
Chronic infection, diarrhea, poor night vision, skin issues, menstrual issues, hypothyroidism and autoimmune disease are all symptoms that relate to insufficient vitamin A. As a fat soluble vitamin it is also possible to have too much. Ensuring that vitamin D and K2 are taken with vitamin A reduces the potential for toxicity which is part of the synergy of whole food supplementing.
Here’s a few food sources: one pastured egg yolk has 800 iu of bioavailable Vitamin A. Four ounces of beef liver has 19 000 iu and I recommend adding it to stew in small amounts or finding a source of good pate. Canned cod liver is another easy source. If you take extra virgin cod liver oil 1 tsp/day is enough. Buy one that’s good quality and treat it like a food meaning take breaks from it regularly as we do with any food in a varied diet.