“For many years, the RDA [recommended daily allowance] for all vitamins were based on preventing deficiency, with a margin of safety,” however the miniscule quantity of vitamin C wanted to keep away from scurvy, for instance, will not be essentially the perfect consumption for optimum health. What may the optimum consumption of vitamin C be? To discover out, let’s ask the physique. But how? By seeing how a lot the physique absorbs and excretes, which I am going by way of in my video What Is the Optimal Vitamin C Intake?.
When we swallow 15 mg of vitamin C, the quantity we’d get eating a few quarter of an orange, our physique absorbs practically 90 p.c of it. If we as an alternative take a complement containing 1,250 mg of vitamin C, our physique appears to understand that’s an excessive amount of and clamps down on absorption on the intestinal lining stage, and we find yourself absorbing lower than half. By doing experiments the place the extent of consumption is ratcheted up slowly, we will see when the physique begins to say, “Okay. That’s enough.”
That magic stage of consumption seems to be about 200 mg a day. When we take as much as 200 mg every day, our physique absorbs all of it. Above that stage, nevertheless, the physique tries to dam additional absorption, suggesting that our “intestinal vitamin C transport mechanisms… have evolved to fully absorb up to about 200 mg of vitamin C” a day.
In addition, vitamin C is reabsorbed in our kidneys again into our bloodstream to keep up our vitamin C blood ranges round 70 or 80 micromoles per liter, which is what we attain at a vitamin C consumption of about 200 mg a day. Even if we take ten occasions as a lot in vitamin C dietary supplements, 2,000 mg a day, our physique will simply pee and poop out the surplus to maintain our blood ranges in that slim vary of 70 to 80 micromoles per liter. Based on these sorts of information, one may “propose that 200 mg is the optimal daily intake of vitamin C…”
We can verify that speculation utilizing illness information. For instance, at what every day consumption of vitamin C is there the bottom stroke danger? Apparently, at about 200 mg a day. While 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 exhibiting that antioxidant dietary supplements usually don’t appear to guard in opposition to coronary heart assaults or strokes.
Is it attainable to rise up to an consumption of 200 mg of vitamin C a day with out taking dietary supplements? No drawback. A single serving of vegetables and fruit might have about 50 mg every, so simply 5 servings of fruits and veggies a day may get us to perfect blood ranges.
Doctors can circumvent our physique’s pure boundaries to vitamin-C overload by dripping excessive ranges of the vitamin immediately into the bloodstream of most cancers sufferers. Is this a good suggestion? See:
What different advantages or drawbacks may vitamin C have? See:
What about different widespread dietary supplements? See, for instance:
Michael Greger, M.D.
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