Published: Nov 11, 2013 | Updated: Nov 12, 2013
By Kristina Fiore, Staff Writer, MedPage Today

Full Story:  http://www.medpagetoday.com/Endocrinology/Diabetes/42850

A diet high in acidic foods — meat, fish, and sodas, for instance — may put some women at greater risk for developing type 2 diabetes, researchers found.

In an analysis of data from the E3N-EPIC cohort, French women with higher scores on a measure of dietary acidity had about a 70% greater risk of developing diabetes than those whose diets were more alkaline, Guy Fagherazzi, PhD, of Gustave Roussy Institute in Villejuif in France, and colleagues reported online in Diabetologia.

Some work has suggested that Western diets rich in animal products and other acidogenic foods may create an acid load that isn’t compensated for by intake of fruits and vegetables.

This can lead to chronic metabolic acidosis, which may play a role in cardiometabolic abnormalities.

To assess whether dietary acid load has an association with development of diabetes, Fagherazzi and colleagues looked at data on 66,485 women from the French E3N-EPIC cohort, all of whom completed several dietary questionnaires.

Dietary acid load was assessed by two scores that are commonly used to estimate dietary acid load in epidemiological studies — the potential renal acid load (PRAL) score and the net endogenous acid production (NEAP) score.

Both scores are derived from nutrient intake. PRAL takes into account intestinal absorption rates of nutrient ionic balances for protein, potassium, calcium, and magnesium, and phosphate. NEAP is based on protein and potassium intake, considered to be the main components involved in acid production.

The women were followed for 14 years, and a total of 1,372 cases of type 2 diabetes developed over that time.

An acidic diet involved higher intake of fat and animal protein, and a lower intake of carbohydrates. It was also linked to a higher intake of phosphorus, calcium, and sodium, as well as lower magnesium. Specific foods constituting an acidic diet included more meat, fish, cheese, bread, and soft drinks, while more alkaline diets involved more dairy products, fruits, vegetables, and coffee.

Fagherazzi and colleagues found that both PRAL and NEAP scores were associated with risk of incident type 2 diabetes.

Women with a high acid load were at higher risk of type 2 diabetes than those with high alkaline load:

• PRAL: HR 1.71 (95% CI 1.40-2.07)
• NEAP: HR 1.74 (95% CI 1.44-2.11)

The risk was slightly attenuated but remained significant after adjusting for body mass index (PRAL: HR 1.56, 95% CI 1.29-1.90, P<0.0001 for trend).

PRAL and NEAP scores were associated with greater risk of type 2 diabetes in both normal-weight and overweight or obese women, but the associations were stronger in normal-weight women than in heavy women (PRAL: HR 1.96, 95% CI 1.43-2.69 versus HR 1.28, 95% CI 1.00-1.64).

The mechanisms behind the association aren’t clear, but some work suggests that imbalances in acid/base homeostasis play a role in some cardiometabolic abnormalities. Chronic metabolic acidosis, for instance, may lead to insulin resistance and the metabolic syndrome, the researchers wrote.

Further work is needed to elucidate those mechanisms, they said, and their results need to be validated in other populations, particularly in men, who were not evaluated in this study.

Also, the study was limited by a single measurement of dietary acid and relied on information from a survey.

Still, Fagherazzi and colleagues said the findings may eventually lead to the promotion of diets with a low acid load in order to prevent diabetes.