Recommending three serves of dairy foods each day makes sense to provide good nutrition and the recommended dietary intake (RDI) of calcium. On the other hand, suggesting the consumption of dairy foods to patients at risk of, or living with, type 2 diabetes may seem counter-intuitive.
Diabetes Australia recommends low-fat dairy foods to help manage type 2 diabetes. This is because there are a number of ways in which dairy foods, especially low-fat varieties, appear to positively influence type 2 diabetes. Dairy consumption may lower the risk of type 2 diabetesNumerous studies have shown dairy consumption to be inversely associated with the risk of type 2 diabetes. A meta-analysis of middle-aged US men and women reported a summary odds ratio for the incidence of type 2 diabetes to be 0.86 (95% CI; 0.79 – 0.93) for the highest (3-5 serves) versus the lowest (<1.5 serves) daily dairy intake. The large, prospective US Health Professionals Follow-up Study concluded that a dietary pattern rich in dairy foods, especially low-fat dairy, may lower the risk of type 2 diabetes in men. Dr Hyon Choi and colleagues followed more than 41,000 males over 12 years. Men who consumed at least three serves of dairy foods daily had a 33% lower risk of developing type 2 diabetes, compared to those in the lowest quintile of intake. Each additional serve of total dairy food intake per day was associated with a 9% lower risk for type 2 diabetes (multivariate RR 0.91; 95% CI 0.85 - 0.97). Another recent prospective study, this time in middle-aged and older women, found a similar result. During 10 years of follow-up, Lui and colleagues documented 1,603 incident cases of type 2 diabetes. After adjustment for risk factors, the relative risk of type 2 diabetes among women in the highest quintile of dairy intake was 0.79 (95% CI 0.67-0.94), compared with those in the lowest quintile. Each serving per day increase in dairy intake was associated with a 4% lower risk for type 2 diabetes. In a study by Ard and colleagues, patients who followed a low sodium, reduced calorie 'DASH' diet, and received standard behavioural intervention for six months, experienced a 34% greater improvement in insulin sensitivity than patients who received comprehensive behavioural intervention alone (p = 0.047). DASH stands for 'Dietary Approaches to Stop Hypertension' and includes low-fat dairy foods, as well as increased fruit and vegetables.Dairy foods: growing evidence for metabolic syndrome protectionA number of studies (in Iraqi men and women, US women, and black and white US young adults) show a negative association between milk consumption and the risk of developing metabolic syndrome, a strong risk factor for type 2 diabetes (Tehran Lipid and Glucose Study, Women’s Health Study, CARDIA study). In the Caerphilly prospective study, a negative association was found between milk and dairy food intake and metabolic syndrome. In 2007, Professor Peter Elwood and colleagues reported the odds ratio in men who regularly drank a pint of milk (600mL) or more daily was 0.38 (95% CI 0.18 to 0.78) and that for total dairy foods consumption was 0.44 (95% CI 0.21 to 0.91). Milk and yogurt have a low GIMilk and yogurt have a low glycaemic index (GI) – the carbohydrate is relatively slowly digested and released into the bloodstream – making them ideal for people with diabetes. According to Dr Jennie Brand-Miller and colleagues, a food with a GI rating of less than 55 can be classed as a low GI food. Milk and yogurt fall well below this cut-off. Most cheeses contain less than 1% carbohydrate, so do not have a GI rating. Table: Calcium content, fat content and GI for some dairy products.
|Dairy product||Fat content(g/100g)||Glycaemic index||Calcium(mg/100g)|
|Whole milk||3.8||27 (ave)||114|
|Chocolate flavoured, low-fat||1.7||34||114|
|Yogurt (low-fat, fruit)||0.2||33||179|
|Yogurt (low-fat, artificial sweetener)||0.2||14||170|
Source: Proximate Composition of Australian Dairy Foods, 1999; The GI Factor, 2000). Low-fat dairy foods may benefit people with type 2 diabetesConsumption of milk, cheese and yogurt is associated with overall diet quality and adequacy of intake of many nutrients. Dairy foods are nutrient-dense foods – they provide substantial amounts of protein, vitamins and minerals, relative to their energy content.Eating low-fat dairy foods as part of a healthy diet may also benefit people with diabetes by helping to reduce obesity, hypertension and blood lipids. For example, a recent randomised clinical trial concluded that a diet rich in dairy calcium intake enhances weight reduction in patients with type 2 diabetes, especially those who have difficulty adhering to other weight reduction diets. Among the highest tertile of dairy calcium intake, the odds ratio for weight loss of >8% was 2.4 (P = 0.04), compared with the tertile who consumed the least dairy calcium. Key points
- Dairy foods, particularly low-fat varieties, have been associated with a reduction in risk of type 2 diabetes (and the metabolic syndrome).
- Milk and yogurt have a low glycaemic index, so can play a beneficial role in helping to control.
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