High Bicarbonate Tied to Lower Diabetes Risk

Women with high plasma levels of bicarbonate are at a decreased risk for developing type 2 diabetes mellitus (DM), according to a new study.

Researchers at Harvard School of Public Health (HSPH; Boston, MA, USA), Maine Medical Center (MMC; Portland, USA), and other institutions conducted a prospective, nested, case–control study involving 630 women who did not have type 2 DM at the time of blood draw in 1989–1990, but developed type 2 DM during 10 years of follow-up. Controls were matched according to age, ethnic background, fasting status, and date of blood draw. The researcher used logistic regression to calculate odds ratios (ORs) for diabetes by category of baseline plasma bicarbonate.

The results showed that after adjustment for matching factors, body mass index (BMI), plasma creatinine level, and history of hypertension, there was a 4% decrease in the likelihood for developing diabetes with each unit increase in bicarbonate. Those in the second, third, and fourth quartiles of plasma bicarbonate had lower odds of diabetes compared with those in the lowest quartile; further adjustment for C-reactive protein (CRP) did not alter these findings. The study was published on July 23, 2012, in the Canadian Medical Association Journal (CMAJ).

“The association between lower plasma bicarbonate and development of diabetes may be explained by metabolic acidosis promoting insulin resistance, and this association may be independent of systemic inflammation,” concluded lead author Ernest Mandel, MD, of HSPS, and colleagues. “The association between bicarbonate and diabetes also may be independent of levels of dietary acid, because they adjusted for factors that influence this, such as intake of animal protein and fruits and vegetables.”

The bicarbonate buffering system is an important part of the acid-base homeostasis of all living things, including humans. As a buffer, it tends to maintain a relatively constant plasma pH and counteract any force that would alter it, managing the many acid and base imbalances that can be produced by both normal and abnormal physiology. It also affects the handling of carbon dioxide (CO2), the constantly produced waste product of cellular respiration.

Related Links:
Harvard School of Public Health
Maine Medical Center