To the many Americans interested in weight loss, vitamin C may be an important factor to keep in mind. How is vitamin C related to fat metabolism? Vitamin C is required for synthesis of carnitine, the molecule responsible for shuttling fatty acids across the mitochondrial membrane to be oxidized for energy. If one does not have sufficient vitamin C, the synthesis of carnitine and downstream fat metabolism could be negatively affected. In fact, reduced tissue carnitine, and its associated impact on fat metabolism, is considered to be the cause of fatigue associated with scurvy.

Research supports this posited relationship between vitamin C and fat metabolism.

• One randomized controlled trial demonstrated that those who supplemented with 3 grams of vitamin C per day showed significantly greater weight loss than a placebo group with similar goals. (Naylor et al. 1985)

• Another study investigated vitamin C status and fat oxidation during exercise, and found that individuals with adequate vitamin C status oxidized 30% more fat during moderate exercise than those with low vitamin C status. (Johnston 2005)

• A cross-sectional trial investigated the relationship between plasma vitamin C, adiposity, and adiponectin (a hormone produced by fat cells that regulates metabolism) concentrations. In both men and women, plasma vitamin C concentration was inversely related to BMI, waist circumference, and body fat. (Johnston et al. 2007)