In the News: Vitamin B6 & Inflammation, Coffee & Exfoliation Glaucoma, Dietary Lycopene & Stroke

Low Vitamin B6 Levels Linked to Inflammation

Previously, studies have identified low vitamin B6 status in patients with inflammatory diseases, including cardiovascular disease, rheumatoid arthritis, inflammatory bowel disease, and diabetes.

Based on those findings, researchers from Tufts, Boston University, and Safra Children’s Hospital conducted the first large-scale study evaluating B6 status and inflammation (1). They report an association between low plasma levels of vitamin B6 and a wide range of inflammatory markers.

The researchers measured 13 individual markers of inflammation and plasma B6 concentrations in a cohort of over 2,200 (55% women, mean age 61 yrs). Plasma B6 levels correlated with a summary score of the inflammatory markers. Those with lower B6 levels were significantly more likely to show signs of inflammation. At the same time, markers of inflammation tended to decrease as vitamin B6 levels rose (p-trend <0.0001). The same associations were not observed with other B-vitamins.

Intervention studies are needed to determine whether improving B6 levels can help curb inflammation. However, it’s worth noting that inadequate plasma B6 is much more common than previously believed in pre-menopausal women, men who smoke, Afro-American men, and people over 65. These 4 groups have the highest rates of low plasma B6 levels according to the results of a recent large-scale study (2).

Lycopene-Rich Diet May Cut Stroke Risk

The results from a prospective Finnish study (3) suggest that high serum levels of lycopene reduce the risk of stroke in men. Lycopene, a carotenoid nutrient, is concentrated in tomatoes and tomato-based foods.

The research team followed over 1,000 men (aged 46-65) for an average of 12 years. Of those with lowest blood levels of lycopene, 25 experienced a stroke, while stroke occurred in 11 of the men with the highest lycopene levels. This amounts to a 55% reduction in stroke risk (p = 0.036), and a 59% risk reduction (p = 0.042), looking at ischemic stroke alone. Blood concentrations of alpha-carotene, beta-carotene, and vitamins A and E were not related to stroke risk.

These results add to the large body of evidence linking high fruit and vegetable intake with a lower risk of stroke, and suggest that consumption of lycopene-rich tomatoes could be especially important.

Can Caffeinated Coffee Raise Glaucoma Risk?

Drinking 3 or more cups of caffeinated coffee a day may increase the odds of developing exfoliation glaucoma by 34% (p-trend = 0.06), compared to abstaining from the beverage (4). The odds may also rise considerably for women with a family history of glaucoma who drink > 3 cups daily (p-trend = 0.06).

Those are the main findings of Harvard and Brigham and Women’s Hospital researchers who followed women in the Nurses’ Health Study (about 79,000) and men from the Health Professionals Follow Up Study (approx. 41,200) who were at least 40 years of age and glaucoma-free.

The participants were followed for 12 years, during which their intake of caffeine-containing beverages was regularly updated. Caffeinated sodas, tea, chocolate, and decaffeinated coffee did not affect risk.

There may be a plausible mechanism to explain the link between heavier caffeinated coffee intake and exfoliate glaucoma. Coffee’s chlorogenic acid has been shown to raise levels of homocysteine, as has caffeine. Elevated homocysteine, in turn, can damage vascular tissue and contribute to dysfunctional extracellular matrix re-modeling. In addition, several studies have found elevated homocysteine in the blood, aqueous humor and tears of people with exfoliation glaucoma.

References

1. Sakakeeny L, et al. Plasma pyridoxal-5-phosphate is inversely associated with systemic markers of Inflammation in a population of U.S. adults. J Nutr 142:1280-5, 2012.
2. Morris MS, et al. Trends of vitamin B6 status in US population sample. AJCN 87:1446-54, 2008.
3. Karppi J, et al. Serum lycopene decreases the risk of stroke in men: A population-based follow-up study. Neurology 79:1540-47, 2012.
4. Pasquale LR, et al. The relationship between caffeine and coffee consumption and exfoliation glaucoma or glaucoma suspect: A prospective study in two cohorts. Invest Ophthalmol Vis Sci 53:6427-33, 2012.