Beneath is an approximation of this video’s audio content material. To see any graphs, charts, graphics, pictures, and quotes to which Dr. Greger could also be referring, watch the above video.
For a few years, the RDA (the advisable each day allowance) for nutritional vitamins was simply based mostly on stopping deficiency with a margin of security. However, the minuscule quantity of vitamin C, for instance, wanted to keep away from scurvy isn’t essentially the best consumption for optimum well being. So, what is perhaps the optimum consumption of vitamin C? Let’s ask the physique. How may we try this? By seeing how a lot the physique absorbs and excretes.
Should you swallow 15 milligrams of vitamin C, which is what you’d get consuming about one-quarter of an orange, your physique sucks up almost 90% of it. However, if you happen to take a complement containing 1,250 milligrams, your physique appears to appreciate that’s an excessive amount of—and so, clamps down on absorption on the intestinal lining stage, and you find yourself absorbing lower than half.
So, by doing experiments the place you slowly ratchet up the extent of consumption, you may see when the physique begins to say, “Okay, that’s sufficient.” And, that magic stage of consumption seems to be about 200 milligrams a day. Once you take as much as 200 a day, your physique sucks all of it up. However, above that, the physique tries to dam additional absorption—suggesting our intestinal vitamin C transport mechanisms “have developed to totally take in as much as about 200 mg of vitamin C” a day.
As well as, vitamin C is reabsorbed in our kidneys, again into our bloodstream, to keep up our vitamin C blood ranges up at round 70 or 80 micromoles per liter. That’s the shaded area right here, which is what you attain at a vitamin C consumption of about 200 milligrams a day. So, even if you happen to take ten occasions as a lot in vitamin C dietary supplements—2,000 milligrams a day—your physique will simply pee and poop it out to maintain your blood ranges in that slim vary. So, based mostly on these sorts of information, one may suggest that 200 milligrams is the optimum each day consumption of vitamin C.
You may verify, utilizing illness knowledge. At what each day consumption of vitamin C is there the bottom stroke danger? Apparently, at about 200 milligrams a day. Whereas dietary vitamin C consumption was related to decrease stroke danger, vitamin C dietary supplements weren’t—which is according to the general physique of proof displaying that antioxidant dietary supplements on the whole don’t appear to guard towards coronary heart assaults or strokes.
However, wait, are you able to stand up to an consumption of 200 milligrams a day with out taking dietary supplements? No downside. Single servings of vegetables and fruit could have about 50 milligrams every; so, a measly 5 servings of fruits and veggies a day may get you to ideally suited blood ranges.
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