As I mentioned last week, I’m taking an Advanced Human Nutrition class this semester which focuses only on micronutrients. My professor concentrates her research on vitamin C, and she is a wealth of knowledge on that vitamin alone. My class has been intense (even from the start) yet fascinating. I briefly discussed the chemistry behind nutrient absorption on Tuesday, and I’m back with some more details on Vitamin C.
Life Lessons on Vitamin C:
- If you peel an orange to take to work that day, by the time you eat it on your lunch break the vitamin C content has completely deteriorated. This is because vitamin C is one of the most fragile of all vitamins and minerals. Vitamin C is easily oxidized and therefore destroyed by oxygen. Humans cannot absorb this oxidized form of vitamin C. To prevent this, leave the peel on your orange and eat it as soon as you remove it. This also applies to your favorite breakfast juice. If you buy orange juice and it sits in your fridge for a few weeks, the vitamin C content will decrease significantly.
- Vitamin C is a natural antihistamine. If you take a large dose of vitamin C (at the time of allergies), your histamine levels fall by 40%. (I personally can’t wait to test this out next allergy season)
- High doses of vitamin C as an IV injection have been used as an alternative treatment for cancer patients. Vitamin C given through an IV in very high doses will produce hydrogen peroxide, in the same way that chemotherapy does and cause oxidative stress to the cancer cells to destroy them.
- Each one of us has slight differences in our genetic codes (called polymorphisms) which interacts with our diets and affects our risk for disease. 30% of the American population has a genetic variation that does not allow us to absorb vitamin C as easily as others. Even if you eat sufficient fruits and vegetables, you may not be absorbing all the vitamin C in them. This results in a 22% difference in vitamin C levels based on if you have this polymorphism or not.
- You will absorb nearly 100% of vitamin C at intakes less than 200 mg. Anything higher than that will be excreted as waste. The human body only has so many receptors available to allow the vitamin to enter cells.
Is anyone else surprised by these facts? I know I was. I left class this week convinced that I had scurvy. Now I’m going to be stress eating oranges in order to max out my vitamin absorption.
The solution? Eat as many raw (and fresh) fruits and vegetables as possible. The RDA (Recommended Daily Allowances) for vitamin C is 75 mg/day for adult women and 90 mg/day for adult men. Foods high in vitamin C include: sweet red peppers (283 mg/cup), papaya (183 mg/cup), strawberries (85 mg/cup), oranges (70 mg/cup), and pineapple (80 mg/cup).