All living organisms on Earth are built only from left-handed amino acid molecules due to the ultraviolet radiation of neighboring stars that surrounded the solar system at the time of its formation, scientists from Japan, Britain, Australia and the United States write in an article posted in the electronic library of Cornell University .
In the chemical synthesis of vitamins, etc. a mixture of right- and left-sided molecules is obtained, which is less absorbed by the body and less effective.
I'll tell you about calcium and vitamin D, because that's what I know well. Hopefully, experts on other vitamins will also be found. This is not true for calcium and vitamin D. Calcium absorption depends on: dose, bioavailability and concentration of active vitamin D in the body. The bioavailability of calcium from food can be affected by the presence of oxalates, which bind calcium and prevent its absorption. Oxalates are found in many lettuce-like leaves, such as spinach. The best source of calcium is, of course, dairy products. Dose: Roughly speaking, the more, the less the percentage will be absorbed (percentage, but not the total). If you want to eat a daily requirement of 1200 mg, then it is better to do it in two doses in the morning and 600 mg in the afternoon. And better with food. Vitamin D is necessary for the active absorption of calcium, therefore, if we are to take calcium, then it makes sense to choose the combined option of calcium + vitamin D. Vitamin D, unlike calcium, is contained in an extremely limited set of food products, so it is impossible to get adequate amounts of it with food ... In theory, we should not eat, but synthesize vitamin D in the skin under the influence of ultraviolet radiation, however, in the middle lane, especially in the city, the synthesis will certainly not be sufficient. There is a lot of controversy around the necessary doses of vitamin D, but in winter, in my opinion, pills are indispensable. There are a lot of products fortified with vitamin D in the USA (milk, orange juice), I think in Russia this is so-so, but this is a good option.