Big Intake of High-Fat Dairy May Be Protective for Diabetes

Becky McCall

September 16, 2014

VIENNA — A large intake of high-fat dairy products appears to be associated with a reduced risk for type 2 diabetes, confirming previous findings of a possible protective effect of dairy fat on the risk of this condition. Low-fat dairy products do not appear to show the same effect.

Specifically, people who consume a large amount (over 8 portions per day in this study) of high-fat dairy products have a 23% lower risk of developing type 2 diabetes than those who consume lower levels (1 or fewer portions per day).

Previous studies have indicated that replacing saturated with unsaturated fats helps to prevent type 2 diabetes, and for this reason plant sources of fat are considered preferable to animal.

Reflecting this, high intakes of red meat and meat products are known to be positively associated with diabetes risk. But high intake of dairy foods, which are also saturated fat, has previously been shown to be protective.

The latest results were presented by epidemiologist Ulrika Ericson, PhD, from Lund University Diabetes Center, Malmö, Sweden, at the European Association for the Study of Diabetes 2014 Meeting.

In an interview with Medscape Medical News, she explained that previous epidemiological studies have indicated a high intake of dairy products is associated with a decreased risk of developing type 2 diabetes, "but it has been suggested that mainly low-fat dairy lies behind the observations."

The findings presented here suggest only high-fat content is protective. In comparison with high-fat dairy products, a large intake of low-fat dairy was associated with increased risk (P for trend = .01) for type 2 diabetes, but this association disappeared after additional adjustment for protein intake (P for trend = .37).

Odd-Chain Saturated Fatty Acids

Previous research led by Nita Forouhi, MD, program leader and public-health physician at the MRC Epidemiology Unit, University of Cambridge, United Kingdom, published in August this year, suggested that molecules with odd numbers of carbon atoms (15 and 17), which are found in dairy products such as yogurt, cheese, and milk, appeared to have a protective effect.

This contrasts with evidence suggesting that even-chain saturated fatty acids, as found in alcohol or margarine, are associated with a greater risk for type 2 diabetes.

Against this background of prior research, Dr. Ericson and her colleagues wanted to clarify the risk for type 2 diabetes associated with the intake of the main dietary fat sources — namely, meat, fish, and dairy.

A total of 26,930 individuals, aged 45 to 74 years, from the population-based Malmö Diet and Cancer cohort, were included. Dietary data were collected, and during 14 years of follow-up, 2860 cases of type 2 diabetes were identified.

Hazard ratios (HR) of diabetes incidence were determined. Adjustments were made for age, sex, season, diet-assessment method version, total energy intake, body mass index (BMI), leisure-time physical activity, smoking, alcohol consumption, and education.

High-Fat Dairy Better

Upon analysis, results showed that high intake of high-fat dairy products, compared with low intake of high-fat dairy, corresponded to a lower incidence of type 2 diabetes (HR for the highest [median = 8 portions/day] compared with the lowest [median = 1 portion/day] intake quintile, 0.77; P for trend < .001).

Specifically, high-fat cream and high-fat fermented milk were inversely associated with risk for type 2 diabetes. High intake of cream (30 mL or more a day in the highest-consuming 20% of the population) vs low intake (0.3 mL a day or less in the lowest-consuming 20%) conferred a 15% reduction in the risk of developing type 2 diabetes.

Similarly, high-fat fermented-milk consumption also reduced the risk of developing diabetes by 20%, when the biggest consumers (180 mL/day in the top 10% of consumers) were compared with nonconsumers (60% of participants).

Meat Intake and Risk

The results in relation to intake of meat and meat products were found to be in line with previous findings. An increased risk for diabetes was found with high intake of meat and meat products regardless of fat content (HR, 1.09; P for trend = .04; and HR, 1.25; P for trend < .001; for high- and low-fat meat, respectively).

Dr. Ericson added that it was well-established that vegetable sources of fat "are considered to be a better choice compared with animal sources of fat, including high-fat dairy products. This is mainly based on the higher content of total saturated fat in animal foods."

Reflecting the possibility that the type of saturated fat has a role to play, Dr. Ericson said that "there are fatty acids, more common in dairy products, that may partly lie behind our observations regarding high-fat dairy," and with respect to meat, she pointed out, "it has been suggested that other components in meat may be detrimental, such as nitrites, salt, or iron."

No Association With Low-Fat Dairy, but Clarification Needed

Asked to comment on the new work, Dr. Forouhi said that overall the reported findings confirmed, in a single study, that higher consumption of certain types of dairy products was associated with lower risk for diabetes, while red and processed meat intake was linked with a higher risk.

"Importantly, the findings add more weight to the growing body of evidence supporting the need to shift the focus of dietary advice away from nutrients like total or saturated fat to the differential healthfulness of food sources like dairy products or meat," she added.

Dr. Forouhi said also that other important factors need to be considered during interpretation of these findings, particularly with respect to the increased or no association between low-fat dairy and type 2 diabetes.

"To place the observed beneficial association with high-fat dairy in context, it is important to tease out if the higher risk or no association of low-fat dairy products with diabetes was because low-fat products have extra added sugar instead, which we know from other research to be detrimental," she noted.

She pointed out that further research is needed to understand the mechanisms underlying the association between high-fat dairy and type 2 diabetes — for example, the role of odd-chain saturated fatty acids, as she and her colleagues had done in their European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct study.

"Other beneficial health effects might be due to other beneficial compounds in dairy, such as probiotics and other nonfat nutrients such as vitamins and minerals."

Drs. Ericson and Forouhi have declared no relevant financial relationships.

European Association for the Study of Diabetes 2014 Meeting; September 16, 2014; Vienna, Austria. Abstract 62

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