Do people on carnivore diets develop scurvy, which is a deadly result of vitamin C deficiency? Basically, the answer is a resounding no. The one exception would be if you attempted to live off a diet of only dried and preserved meats. That type of diet is the reason British sailors developed scurvy. For months at a time, they lived off dried, salted meats while they traveled the sea. High-carbohydrate items comprised the rest of their diets, and those foods potentially made matters worse.
Vitamin C has numerous roles in the body. One role is to assist in the synthesis of collagen, which is a vital protein used structurally throughout the body. When collagen synthesis is down, we see some of the classic symptoms of scurvy, such as bleeding gums, loss of teeth, joint dysfunction, and nonhealing wounds. The body also uses vitamin C to help form carnitine, and vitamin C acts as an antioxidant that plays a role in modulating our immune systems. Humans who are deficient in vitamin C start to show signs of scurvy within a few months.
Okay, so if vitamin C is necessary, meat doesn’t contain vitamin C (at least according to the U.S. Department of Agriculture), and humans can’t make vitamin C, what gives? Why are so many people who follow an all-meat diet not walking around with their teeth falling out? Well, several things are in play.
It has been known for well more than 100 years that meat, particularly fresh meat, both cures and prevents scurvy. This evidence was well documented among many nineteenth-century Arctic explorers. Fresh meat is the key difference in a modern carnivore’s diet compared to the diets of the British sailors, which was dominated by dried, salted meat.
Amber O’Hearn, a brilliant long-term carnivore, investigated the USDA’s claim that meat has no vitamin C. She was shocked to discover that the USDA had never bothered to test for vitamin C in meat. As it turns out, meat does contain a small but sufficient amount of the vitamin, particularly in the context of a fully carnivore diet.
Vitamin C enters your body through the intestinal tract. Interestingly, glucose can directly compete with vitamin C absorption because they share a cellular transporter. If there’s a lot of glucose in your system, vitamin C absorption is effectively inhibited. In a meat-only diet, glucose is effectively zero in the intestines; thus, vitamin C becomes more available. Interesting work coming out of the Paleo Medicina group in Hungary has shown that serum vitamin C levels are normal in patients who follow a carnivore diet. In fact, animal-derived vitamin C was more effective than similar plant-derived vitamin C for maintaining serum levels.
Dietary antioxidants are widely believed to benefit us, although there are some significant challenges to that theory. As I mentioned previously, vitamin C has a role here. It’s interesting to note that when an animal that can manufacture its own vitamin C starts eating a carbohydrate-restricted diet, the animal’s synthesis of vitamin C decreases. It’s almost as if eating carbohydrates increases the requirements for antioxidants. Although humans can’t make vitamin C as other animals can, in the presence of a low-carbohydrate diet, we see an increase in some of our endogenous antioxidants (that is, our body makes them).
The role of vitamin C in helping to form collagen involves the hydroxylation of the amino acids proline and lysine to form hydroxyproline and hydroxylysine, respectively. When you eat a meat-rich diet, some of those molecules are absorbed in the already hydroxylated form via specific gut transporters; therefore, you likely require less vitamin C.
The upshot is that when you’re on an all-meat diet, vitamin C absorption is more efficient, and your body’s requirements for it go down. You get a sufficient amount of the vitamin from the food (fresh meat) you eat, and you don’t get scurvy.
Excerpted from The Carnivore Diet, By Dr. Shawn Baker.
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