High Protein Diets Increase Risk For Diabetes: Update

Some people were concerned that the information in this post from September 2011 was from an oral presentation and had not undergone peer review. It has since been published:

High Intakes Of Protein And Processed Meat Associate With Increased Incidence Of Type 2 Diabetes, British Journal of Nutrition, August 2012

In fact, abstracts accepted for presentation do undergo peer review. Mine did. Peer review is a nail-biting experience, not least of which for the egos involved. But, that's probably true everywhere.

Abstract:

"Diets high in protein have shown positive effects on short-term weight reduction and glycaemic control. However, the understanding of how dietary macronutrient composition relates to long-term risk of type 2 diabetes is limited. The aim of the present study was to examine intakes of macronutrients, fibre and protein sources in relation to incident type 2 diabetes.

In total, 27 140 individuals, aged 45–74 years, from the population-based Malmö Diet and Cancer cohort, were included. Dietary data were collected with a modified diet history method, including registration of cooked meals. During 12 years of follow-up, 1709 incident type 2 diabetes cases were identified. High protein intake was associated with increased risk of type 2 diabetes (hazard ratio (HR) 1·27 for highest compared with lowest quintile; 95 % CI 1·08, 1·49; P for trend = 0·01). When protein consumption increased by 5 % of energy at the expense of carbohydrates (HR 1·20; 95 % CI 1·09, 1·33) or fat (HR 1·21; 95 % CI 1·09, 1·33), increased diabetes risk was observed. Intakes in the highest quintiles of processed meat (HR 1·16; 95 % CI 1·00, 1·36; P for trend = 0·01) and eggs (HR 1·21; 95 % CI 1·04, 1·41; P for trend = 0·02) were associated with increased risk. Intake of fibre-rich bread and cereals was inversely associated with type 2 diabetes (HR 0·84; 95 % CI 0·73, 0·98; P for trend = 0·004).

In conclusion, results from the present large population-based prospective study indicate that high protein intake is associated with increased risk of type 2 diabetes. Replacing protein with carbohydrates may be favourable, especially if fibre-rich breads and cereals are chosen as carbohydrate sources."

This was a large and prospective study with more rigorous data collection than studies of the type (it didn't rely solely upon self-reported questionnaires), all of which increase the internal validity, or make the findings more believable.

Eggs and processed meats (e.g. bacon, ham, sausage, deli meats, luncheon meats, hot dogs) were especially risk-laden. However, replacement of protein with carbohydrate, especially fiber-rich breads and cereals, decreased diabetes risk.
________