Beneath is an approximation of this video’s audio content material. To see any graphs, charts, graphics, photographs, and quotes to which Dr. Greger could also be referring, watch the above video.
For a few years, the RDA (the really useful every 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 shouldn’t be essentially the best consumption for optimum well being. So, what may be the optimum consumption of vitamin C? Let’s ask the physique. How may we do this? By seeing how a lot the physique absorbs and excretes.
When 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 degree, and you find yourself absorbing lower than half.
So, by doing experiments the place you slowly ratchet up the extent of consumption, you’ll be able to see when the physique begins to say, “Okay, that’s sufficient.” And, that magic degree of consumption seems to be about 200 milligrams a day. Whenever 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 advanced to completely 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 varieties of knowledge, one may suggest that 200 milligrams is the optimum every day consumption of vitamin C.
You may affirm, utilizing illness knowledge. At what every day consumption of vitamin C is there the bottom stroke threat? Apparently, at about 200 milligrams a day. Whereas dietary vitamin C consumption was related to decrease stroke threat, vitamin C dietary supplements weren’t—which is per the general physique of proof exhibiting 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 fruit and veggies might have about 50 milligrams every; so, a measly 5 servings of fruits and veggies a day might get you to supreme blood ranges.
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