In the News: Vitamin C in Heart Failure, Diabetes Risk; Vitamin D & Rhinitis

Vitamin D and Chronic Rhinitis: A Connection?

Chronic rhinitis is a common condition with multiple causes, and is characterized by inflammation of the inner lining of the nose. People with rhinitis suffer from symptoms such as a runny and itchy nose, nasal congestion, and sneezing. And chronic rhinosinusitis (CRS), inflammation of the nose and sinuses, is actually one of the most common health challenges, affecting an estimated 14% of US adults.

When it comes to vitamin effects on the immune system, vitamin D is one that takes center stage. Researchers are interested in this vitamin because it directly affects many cells (e.g. dendritic cells and macrophages) that are involved in immune and other processes underlying nasal and sinus inflammation.

Studies (1) have found low levels of vitamin D in patients with CRS and allergic fungal rhinosinusitis, and those low levels correlated with elevated levels of dendritic cells. Insufficient blood levels of vitamin D have also been observed in Afro-Americans with CRS compared with age and sex matched healthy controls.

More research is needed to better understand the relationship between vitamin D and CRS, allergic and chronic rhinitis. But in the meantime, it’s a good idea to get enough vitamin D for many reasons including bone and possibly heart health.

Low Vitamin C Linked to Inflammation in Heart Failure, Plus Diabetes Risk

Low intake of vitamin C is not uncommon, and can adversely affect our health. Just last year, for example, researchers found that heart failure patients who didn’t consume enough vitamin C had higher levels of inflammation as measured by the biomarker CRP (2).

Those heart failure patients with low C intake and more inflammation were twice as likely to die of cardiovascular disease within a one-year follow-up. Nearly 40% of the patients had inadequate intake of the vitamin.

Getting adequate vitamin C has also been linked to the risk of developing diabetes.

In the most recent study to explore this relationship, researchers looked at blood levels of vitamin C and hemoglobin A1c (one of the best measures of diabetes risk) among non-diabetic participants in the U.S. National Health and Nutrition Examination Survey (NHANES) (3).

The investigators saw a clear relationship between low blood levels of the vitamin and higher risk for diabetes (higher A1c) that was more pronounced in people 18-44 years old, in women, and in those of Hispanic origin.

Vitamin C and D Interact

In the same study, blood levels of vitamin D were also examined, since high rates of vitamin D deficiency have been found in people that are obese, and past studies have also linked low vitamin D levels to type 2 diabetes.

The link between poor vitamin C status and diabetes risk was even more pronounced in younger and female NHANES participants who additionally had lower vitamin D blood concentrations.

Interactions between these two vitamins have been identified in other studies: Vitamin C is needed to turn vitamin D into its active form within the body. The current findings suggest that this interaction may be important. So be sure to get some sunshine, eat lots of vitamin C-rich fruits and vegetables, and take a daily multi-nutrient supplement that includes both vitamins C and D.

References

1. Waleed M, et al. Review. Vitamin D and chronic rhinitis. Curr Opin Allergy Clin Immunol 12:13-17, 20012.
2. Song EK, et al. Vitamin C Deficiency, High-Sensitivity C-Reactive Protein, and Cardiac Event-Fee Survival in Patients with Heart Failure. Circulation 124:A14667, 2011.
3. Kositsawat J and Freeman VL. Vitamin C and A1c relationship in the National Health and Nutrition Examination Survey (NHANES 2003-2006. J Am Coll Nutr 30:477-483, 2011.