vitamin c
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Vitamin C supplements may be needed to quell the rising problem of insulin resistance among grade-school aged children.[1]

The advice that fruits and vegetables provide sufficient amounts of vitamin C is being questioned in a newly published study. Diabetes is of growing concern and has its roots in early life. Insulin resistance, where living cells don't adequately utilize insulin to produce cellular energy as they once did, is an early feature of diabetes.

Over 2000 children ages 9-10 years underwent blood tests and food intake surveys to determine their metabolic fitness. The strength of the study was that actual blood concentrations of vitamin C were obtained rather than estimations of vitamin C intake from foods.

Lower blood plasma vitamin C concentrations were associated with higher levels of insulin resistance; vitamin C supplement users achieved blood plasma levels that were more efficacious.

Researchers concluded that maintenance of higher vitamin C blood levels, 30 micromole/Liter (µM) above the mean of about 90 µM was associated with "appreciably lower insulin resistance."

However, while there were individuals who exhibited greater than 90 µM blood plasma concentration of vitamin C, all six ethnic groups of children studied as a whole (Europeans, Blacks, East Indians, Pakistanis/Bangladeshis), averaged vitamin C blood concentrations below 90 µM.

While there were no cases of abject vitamin C deficiency reported (scurvy, with accompanying bleeding or hemorrhage), the groups of children in this study, that consumed about 80 milligrams of vitamin C from their daily diet, were all marginally deficient.

A lab test would likely say all of these children were within the "reference range" for vitamin C, which is deceptive. Since they were all deficient, they were all within the "normal but deficient range." Given that the optimal range is 120 µM or more, these children were far from achieving the optimal healthy range.

The study suggests 200 or more milligrams of vitamin C would be needed to achieve adequate blood levels of vitamin C to effectively reduce insulin resistance. Adults, who have larger bodies, will likely require more. And even then, supplemental vitamin C would have to be consumed throughout the day to maintain high blood levels as vitamin C is rapidly excreted within hours through urine flow.

Eating three oranges a day with 60 mg vitamin C per fruit would provide about 180 mg per day. It is obvious that most children aren't going to consume three oranges a day, or kiwis, or papayas, all which are vitamin C-rich fruits. Dietary supplements are in order.


Comment: And if they are insulin resistant, the fruits may only add to the burden:

Cost of C
"At 62 mg of vitamin C per orange, it takes eight oranges to equal the ascorbic acid in one single 500 mg tablet. Eight oranges can cost eight dollars. The vitamin C tablet can cost two cents. That means vitamin C supplements are four hundred times cheaper than eating right. If those oranges were only 25 cents each, their vitamin C still costs 100 times more than the supplement."

- Andrew W. Saul
The percentage of children who consumed vitamin C dietary supplements ranged from 5% to 23% in the six groups studied. Slow-release vitamin C pills were suggested by researchers as a way to help maintain blood levels. Another way is to include of bioflavonoids with vitamin C, which slows its absorption and helps maintain optimal levels.[2]

An era of change

A few decades ago, the New York Times reported that supplementing with vitamin C produces nothing more than expensive urine. This finding was later corrected but never retracted or corrected in the news media.

A New York Times report published in 1981 declared: "The megadose mythology has more than 75 million Americans excreting the most expensive urine in the world, since most of the vitamins and minerals consumed in excess of what the body truly needs are rapidly eliminated." [3]

While the "most expensive urine in the world" tag has been indelibly etched in the public's mind in regard to vitamin C supplements for decades, no mention was made that water-soluble drugs are subject to the same fate. Drugs, priced far above what dietary supplements cost, would be even more "expensive." Yet vitamin C supplements taken in adequate doses are more efficacious than drugs at preventing diabetes, heart disease, stroke, and other progressive diseases.[4]

Nobel Prize laureate Linus Pauling was pilloried by some critics for his advocacy of mega-dose vitamin C. Only in recent times has it been revealed that mega-dose oral or intravenous vitamin C can raise vitamin C levels to the point where hydrogen peroxide is transiently produced to selectively kill cancer cells. Vitamin C therapy for cancer is now being reconsidered.[5]

Bottom line: don't be reticent to give your children extra vitamin C. Turning things around in modern medicine is going to take time. Even the investigators got things backwards when they cited earlier studies saying: "diabetes and insulin resistance were unlikely to be primary causes of low vitamin C concentrations." It's the other way around: low vitamin C levels induce insulin resistance.

References

1. Donin AS, et al, Fruit, vegetable and vitamin C intakes and plasma vitamin C: cross-sectional associations with insulin resistance and glycaemia in 9-10 year-old children. Diabetic Medicine 33:3, 307-315, March 2016. http://onlinelibrary.wiley.com/doi/10.1111/dme.13006/full

2. Vinson JA, Bose P, Comparative bioavailability to humans of ascorbic acid alone or in a citrus extract. American Journal Clinical Nutrition 48: 601, Sept. 1988. https://www.ncbi.nlm.nih.gov/pubmed/3414575 and http://www.sportroninternational.com/pdf/clin_trials/vitcst5.pdf

3. Brody, Jane E., Deficiencies of vitamins. New York Times, March 29, 1981. http://www.nytimes.com/1981/03/29/magazine/deficiencies-of-vitamins.html?pagewanted=all

4. http://orthomolecular.org/resources/omns/v07n14.shtml
http://orthomolecular.org/resources/omns/v06n20.shtml

5. http://orthomolecular.org/resources/omns/v12n19.shtml
http://orthomolecular.org/resources/omns/v12n08.shtml
http://orthomolecular.org/resources/omns/v04n19.shtml

To learn more:

Kurl, S., T. P. Tuomainen, J. A. Laukkanen, et al. "Plasma vitamin C modifies the association between hypertension and risk of stroke." Stroke 33:1568-1573, Jun 2002.

Shargorodsky, M., O. Debby, Z. Matas, et al. Effect of long-term treatment with antioxidants (vitamin C, vitamin E, coenzyme Q 10 and selenium) on arterial compliance, humoral factors and inflammatory markers in patients with multiple cardiovascular risk factors. Nutr Metab (Lond) 7 :55, Jul 6, 2010.

Pfister, R., S. J. Sharp, R. Luben, et al. Plasma vitamin C predicts incident heart failure in men and women in European prospective investigation into cancer and nutrition-Norfolk Prospective Study." Am Heart J. 162:246-253, Aug 2011.