My latest blog for the American Society for Nutrition looks at folate fortification and how sometimes when you take one step forward, you inadvertently take two steps back…
In the 1800s, clinical trials administering cod liver oil (a source of Vitamin D) to tuberculosis patients provided early evidence of its clinical benefit. In 1859, sanatoriums used heliotherapy (exposure to sunlight) as a means to increase tuberculosis patient’s vitamin D intakes. And in case you’re wondering, Vitamin D exerts its effect by binding to and modulating key members of the immune system including T cells, B cells, macrophages and dendritic cells.
I learned about this fact from:
AR Martineau. 2012. Old wine in new bottles: vitamin D in the treatment and prevention of tuberculosis. Proceedings of the Nutrition Society, 71, 84-89.http://journals.cambridge.org/download.php?file=%2FPNS%2FPNS71_01%2FS0029665111003326a.pdf&code=09e65cdc6b159acb91f4e05f6aebbcf2
J Rodrigo Mora, M Iwata, U von Andrian. 2008. Vitamin effects on the immune system: vitamins A and D take center stage. Nat Rev Immunol, 8(9)685-698. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906676/pdf/nihms185109.pdf
On my almost annual family trips to Florida, a visit to the local used bookstore has become a tradition.
On my latest trip I found quite a treasure…an original copy of Linus Pauling’s Vitamin C and the Common Cold.
Today, the scientific consensus is that vitamin C does not reduce the incidence of the common cold, but rather, will only reduce the severity and duration. However, considering the lack of agreement among studies in combination with yesterday’s post, this may be yet another example of confusion arising from trials on genetically heterogeneous populations. Who knows…only future research will tell. And until then, eat your citrus, because when it comes to fruit, you can’t go wrong!!
I learned about this fact from:
Pauling, Linus. Vitamin C and the Common Cold. W.H. Freeman and Company; San Francisco: 1970.
Douglas RM, Hemilä H, Chalker E, Treacy B. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2007 Jul 18;(3):CD000980.
And a recent study showed that people who consume more vitamin C have a larger pool in their muscles.
This is important because Vitamin C plays a crucial role in muscle tissue. First, it functions as an antioxidant and helps protect muscle tissue from the potentially damaging free radicals that can be produced during exercise. And second, it’s also an enzyme, and consequently acts as a cofactor in the production of collagen and carnitine.
But keep in mind, you don’t need to take a supplement to ensure sufficient levels of vitamin C, it’s one of those nutrients that’s found in tonnes of foods (mainly fruits and vegetables), and they’re your best source.
I learned about this fact from: Carr AC, Bozonet SM, Pullar JM, Simcock JW, Vissers MC. 2013. Human skeletal muscle ascorbate is highly responsive to changes in vitamin C intake and plasma concentrations. Am J Clin Nutr 97(4):800-7. doi: 10.3945/ajcn.112.053207.
This is largely because with every day of storage, vitamin C levels decrease by about 2%. Nevertheless, this does not necessarily mean that re-constituted juice is better, as the rate of vitamin C degradation may be greater in re-constituted juice. Therefore, the bottom line is, don’t leave juice in your fridge for too long, its benefits will decrease.
—I learned about this fact from: Terry LA, ed. Health-promoting properties of fruits and vegetables. CABI: Cambridge, 2011.
As the story goes, Christiaan Eijkman, a Dutch doctor in Indonesia in the 1880s, was conducting an experiment to see if bacteria were responsible for a disease called “beriberi”.
At first, Eijkman couldn’t figure out why all of his chickens were getting sick. Then out of nowhere, they started getting better. After a chat with the chicken-keeper, Eijkman realized that initially the chickens were being fed leftover white rice that was donated from the hospital next-door. But after the hospital cook stopped providing them with these leftovers, the chicken-keeper started feeding the chickens brown, unpolished rice. Then, out of nowhere, the chickens recovered.
This is what ultimately led to the discovery of what Eijkman called the “anti-beriberi factor”, or what we call “Vitamin B1”.
—I learned about this fact from: “Christiaan Eijkman, Beriberi and Vitamin B1.” Nobelprize.org.20 Sep 2012. http:www.nobelprize.org/educational/medicine/vitamin_b1/Eijkman.html
Sun exposure is one of many factors (including soil quality, growing temperature, rain etc.) that influence vitamin and mineral levels in fruits and vegetables. That being said, if you find yourself in an orange grove, opt for a fruit grown on the outside of the canopy as the trees in the middle tend to be more heavily shaded and would thus contain less vitamin C. Moreover, if you’re in the northern hemisphere, fruits on the south side of the tree would likely have greater exposure and thus higher vitamin C levels, compared to fruits grown on the north side. Of course, the situation would be vice versa in the southern hemisphere.
–I learned about this fact from: Terry LA, ed. Health-promoting properties of fruits and vegetables. CABI: Cambridge, 2011.