Avoid deficiency of vitamin C
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Dr. Fiona Harrison of Vanderbilt University speaks at the International Symposium on Vitamin C at the Plaza Hotel in central Seoul, Tuesday. / Korea Times photos by Shim Hyun-chul
By Kwon Ji-youn
It is important to avoid a deficiency of vitamin C rather than supplementing above optimal, according to Dr. Fiona Harrison of Vanderbilt University.
Her research has focused mainly on the damage vitamin C deficiency can do, not the benefits huge amounts of supplementation can have.
“Changes in the brain can be slowed down with adequate vitamin C,” Harrison told The Korea Times at the Plaza Hotel, Tuesday. “We use mouse models that have specific genetic manipulations, so that we can control vitamin C levels in the brain.”
She found that mice with low brain vitamin C levels develop signs of Alzheimer’s disease earlier, causing learning and memory problems, and other changes in the brain that would not be seen until many months later.
“This could be relevant to humans,” she said. “Our studies do not show that vitamin C can cure Alzheimer’s and they are all pre-clinical, but it does seem to show that deficiency can speed the onset of learning and memory problems.”
She explained that in the United States, statistics show that if the onset of Alzheimer’s could be slowed by five years, the number of diagnoses of cases could be cut by 50 percent. She added that vitamin C deficiency speeds up the onset of other related diseases.
“Everybody ages and loses speed of processing in the brain, and changes occur, such as oxidative stress,” she said. “This happens in normal aging, but more and more of an extent in diseases.”
Harrison, who is fascinated by vitamin C and its role in human health, also stressed that while it doesn’t seem possible to have too much vitamin C, none of her research supports the use of high dosages.
“We have specialized transporters in the intestines that carry vitamin C into the blood,” she explained. “Any unused vitamin C is excreted, but in specific medical cases, like those who are prone to kidney stones, it could be damaging.”
Harrison noted that other studies seem to have proven that it is difficult to see the benefit of supplements. “Because we’re limited by the transporters as to how much we can take at a time, there seems to be no point in taking too much,” she said.
She said that it is difficult to assess exactly what the optimal amount of vitamin C would be, but in a study in which she used a specific transporter for the brain and varied it using genetic manipulation, the decrease was 20 to 30 percent of normal brain levels with 500 milligrams, which was enough to help learning and memory.
“Anything more may not be worth taking,” she said.
And while her studies have yet to be peer-reviewed, she uses a specific mouse model with two mutations, which helps express the beta amyloid protein and the pathology associated with it. Beta amyloids are peptides that are the main component of the amyloid plaque found in the brains of Alzheimer’s patients.
“We use large numbers of mice so that we can be as confident as we can be in our statistics, and we’re very careful in our methods,” she said.
Harrison hopes to expand her studies into prenatal development.
“Vitamin C is crucial throughout development,” she said. “Aging starts as soon as we’re conceived so I’m also interested in the role of vitamin C in the brain then.”