Vitamin C (ascorbate or ascorbic acid) is a water-soluble vitamin. The main dietary vitamin C sources are citrus fruit, kiwi, mango, and peppers. A meta-analysis of 15 cohort studies indicated that subjects with the highest intake of vitamin C had 16% lower risk of CHD compared with subjects with the lowest vitamin C intake (Ye and Song 2008). A number of clinical trials have found an inverse association between plasma concentration of vitamin C and markers of endothelial dysfunction and/or inflammation; however, recent studies indicate that there is no significant association between vitamin C intake and cardiovascular events (Goszcz et al. 2015). Finally, the Cochrane review on antioxidants concludes that vitamin C has no significant inverse association with all-cause mortality (Bjelakovic et al. 2012).
Carotenoids and Vitamin A
Carotenoids are lipid soluble and include more than 600 compounds, but the most common carotenoids in the human diet are a-carotene, p-carotene, p-cryptoxanthin, lycopene, lutein, and zeaxanthin. Vitamin A (retinol) can be synthesized from P-carotene in the gut. Carotenoids are found in fruits and vegetables. High levels of carotenoids in the plasma are associated with reduced oxidative stress, improved endothelial function, and lower levels of inflammation (Hozawa et al. 2007). Higher plasma levels of a-carotene and p-carotene are associated with a lower incidence of atherosclerosis (D’Odorico et al. 2000). Lycopene, which mainly derives from tomato intake, is associated with a reduced risk of myocardial infarction and reduced risk of mortality in subjects with high levels of lycopene in adipose tissue (Kohlmeier et al. 1997). The U.S. Preventive Task Force does not recommend p-carotene supplementation for the prevention of CVD (Montalescot et al. 2013).