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Posted August 15, 2009: by Bill Sardi
The latest data on the status of vitamin C deficiency in the US population has just been published, and while it shows a significant reduction in the percentage of Americans who are truly deficient, particularly among low-income and ethnic groups, still ~7% of the US population exhibit signs of overt deficiency (called scurvy), an embarrassing fact for a country that has abundant food supply, fortifies foods and takes vitamin supplements.
Strikingly, the study found that a significantly lower percentage of African and Hispanic Americans exhibit vitamin C deficiency compared to White Americans.
The most arresting fact is that the spectrum of vitamin C deficiency/adequacy appears to follow along the same lines as the rates of disease and mortality in the population. Smokers and low-income groups who typically exhibit low blood serum concentrations of vitamin C also have the highest rates of disease and mortality.
While this study reflects data collected for the period of 2003-04, which shows dramatic improvement over the period 1988-94, the improvement in vitamin C status can largely be explained by fewer smokers since fruit and vegetable intake did not increase. Predictably smokers exhibited a blood concentration of vitamin C, about a third lower than non-smokers.
Smokers in this study, while more likely to exhibit true deficiency, had a mean vitamin C blood concentration ranging from 35.2 in males to 38.6 in females, which is three times higher than the definition of a truly deficient state (11.4 millimole per liter). So it is obvious that the absence of deficiency does not describe a truly healthy vitamin C blood concentration.
It is known that smokers exhibit higher risk for cataracts that cloud vision and for weak blood vessels (aneurysms) which can burst and result in hemorrhage and death.
A much larger proportion of the US population may still suffer adverse health consequences from low vitamin C levels even though they do not fit the definition of deficiency, below 11.4 millimole per liter of blood serum as used in this study.
In fact, the report indicates blood concentrations of vitamin C up to 28 micromole per liter of blood serum still present a modest risk for developing vitamin C deficiency, obviously due to factors like smoking or disease which increase the demand for this vitamin.
About 22% of the subjects in this study had blood concentrations of vitamin C at or below 28 micromole per liter, which is 245% higher than the deficiency level (below 11.4). This data says more Americans are at risk for deficiency symptoms than the synopsis of the report indicates.
The report describes the overt symptoms of vitamin C deficiency (also known as scurvy), which includes anemia, fatigue, bleeding gums, loosened teeth, pinpoint red skin hemorrhages and irritability.
The range of vitamin C concentration in blood serum among all study participants ranged from below 6.2 to 120.8 micromole per liter, a 750-fold difference! It is unlikely any individual achieved optimal vitamin C blood concentration without the use of dietary supplementation.
Vitamin C supplementation, while reducing the percentage of study participants who were deficient from ~7% to ~2%, did not completely eradicate deficiency. This means many vitamin C supplements which provide RDA levels of vitamin C (60 milligrams) are unlikely to eliminate vitamin C deficiency.
In an era of limited healthcare dollars and inevitable insolvency of Medicare, it is tempting to extrapolate the data in this study into practical outcomes. The peak mean vitamin C blood concentration for adult males was 52.5 millimole and for adult females was 62.9 millimole. This is a notch below the 73.8 micromole level that was found in a study published by National Institutes of Health researchers in the year 2000 which showed that blood plasma concentrations that exceeded the 73.8 micromole level experienced a 57 percent reduced risk of dying from any cause and a 62 percent reduced relative risk of dying of cancer when compared to adults who consumed low amounts of vitamin C (28 micromole blood concentration). [American Journal Clinical Nutrition 72: 139-45, 2000]
According to the data and definitions used in this study, ~21 million Americans have frank vitamin C deficiency, ~66 million may develop vitamin C deficiency depending upon their health habits and disease status, and less than 30 million Americans achieve optimal vitamin C levels (~100 micromole per liter).
The study was conducted among 7277 Americans over 6 years of age. [American Journal Clinical Nutrition 2009 August 12]
Once again, this study dispels the mistaken idea that oral doses of vitamin C beyond 200 milligrams do not significantly raise blood concentrations, which was based upon a flawed study conducted by researchers at the National Institutes of Health in the 1990s. [Proceedings National Academy Science 93:14344-8, 1996] More recent studies show oral mega-doses of vitamin C (3000 mg every 4 hours) can produce blood concentrations of vitamin C (220 micromole per deciliter) that are 3 times greater than what was once believed to be the maximum concentration that could be achieved (70-85 micromole). [Annals Internal Medicine, April 6, Volume 140: pages 533-37, 2004]
Steve Hickey PhD, a British pharmacologist, has reported that it takes ~500 milligrams of oral vitamin C consumed at equal intervals, five times a day, to reach optimal blood concentrations. This is because vitamin C is a water-soluble nutrient that is rapidly excreted in the urine.
The Recommended Daily Allowance (RDA) for vitamin C was established for healthy Americans and does not apply to a significant portion of the American population. Smokers (50 million), estrogen or birth control pill users (13 million and 18 million), diabetics (16 million), women during pregnancy (4 million) and people taking aspirin (inestimable millions) or other drugs, and those with chronic infection (viral hepatitis, herpes, HIV, papilloma virus) have increased need for vitamin C and comprise more than 35 percent of the population. The Daily Value for vitamin C, which is widely published on food and supplement labels, is woefully out of date and misleading. #### -Bill Sardi, Knowledge of Health, Inc, August 2009
Source: Schleicher RL, Carroll MD, Ford ES, Lacher DA, Serum vitamin C and the prevalence of vitamin C deficiency in the United States: 2003-2004 National Health and Nutrition Examination Survey (NHANES). American Journal Clinical Nutrition 2009 Aug 12 online]
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