Hundreds of studies, most of them conducted in Western countries, have tied higher intakes of fruits, vegetables, nuts, beans, lentils and fish to a lower risk of coronary heart disease, stroke and Type 2 diabetes.
Now, findings from McMaster University in Hamilton extend the power of such a healthy diet on a global scale.
What’s more, the results indicate that whole fat dairy belongs in this portfolio of protective foods.
About the global study
The latest findings come from the Prospective Urban Rural Epidemiology (PURE) study, a large-scale, long-running multinational study involving 166,762 individuals, 35 to 70 years of age, from 21 low, middle- and hig- income countries on five continents.
For the current study, the researchers used dietary data previously collected from PURE participants to develop a new “PURE healthy diet score.”
They then examined the relationship between participants’ healthy diet scores and the risk of premature death and cardiovascular disease in the PURE study, as well as in five independent international studies with a total of 97,000 participants.
The PURE healthy diet score
The diet score was based on six food categories – fruit, vegetables, legumes, nuts, fish, dairy (mostly whole fat) – each of which has been associated with longevity in past studies.
Fruit included fresh fruit; dried and canned; fruit juices were excluded. Vegetables excluded potatoes, canned vegetables and pickles.
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Legumes included beans (kidney beans, black beans, pinto beans, navy beans, lentils, chickpeas) and peas and black-eyed peas. Dairy included milk, yogurt, yogurt drinks, cheese and mixed dishes prepared with dairy; butter and whipped cream were excluded.
A value of 0 (unhealthy) to 1 (healthy) was assigned to each of the six components, based on a participant’s intake of each. Diet scores ranged from 0 to 6, with higher scores indicating a healthier diet.
Participants in the group with the highest diet scores achieved a score of at least five.
They consumed, each day, five servings of fruits and vegetables, about one-quarter cup of nuts (28 g) and two dairy servings, mainly from whole fat milk, yogurt and/or cheese. (One serving of dairy was defined a one cup of milk, one cup of yogurt or one-half ounce of cheese.)
Their diets also consisted of three to four one-half cup servings of legumes and 6.5 ounces of fish each week.
Compared to PURE study participants with the lowest healthy diet scores (one point or less), those with the highest scores were 30 per cent less likely to die of any cause over the nine-year study period.
They also had a significantly lower risk of heart attack, stroke and death from cardiovascular disease.
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The researchers accounted for other risk factors that could influence the results, including age, waist circumference, physical activity, smoking status, history of diabetes and socioeconomic status.
Similar protective effects were observed for having a high PURE diet score in the five independent international studies.
A notable strength of this new study is its size and diversity; it included 244,957 people from 80 countries at different economic levels from five continents.
Whole fat versus low fat dairy
This isn’t first the study to suggest that whole fat dairy – e.g., milk and yogurt with 3.3 per cent milk fat, cheese with 31 per cent milk fat – provides health benefits.
Findings from recent observational studies suggest that higher intakes of dairy, including whole fat dairy, may protect from heart disease, stroke and death from cardiovascular disease.
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Previous data from the PURE study, published in 2020, showed that consuming two to three servings of dairy a day (versus none) was associated with a lower risk of developing hypertension and Type 2 diabetes. Whole fat dairy was especially beneficial.
Whole fat dairy contains potentially beneficial compounds including high quality protein, unique fatty acids and many vitamins and minerals. As well, bioactive peptides (short chains of amino acids) in fermented dairy products (yogurt, cheese) are thought to improve how the body uses insulin.
These new findings don’t mean you should fill up on ice cream and cheese.
Rather, the takeaway is that two daily servings of whole fat dairy (milk, yogurt and/or cheese) can be part of a healthy diet – and here’s the key – a diet that also contains decent amounts of fruits, vegetables, nuts, legumes and fish.
Keep in mind, too, that this healthy PURE diet isn’t high in saturated fat. It’s in line with Health Canada’s advice to consume less than 10 per cent of daily calories from saturated fat.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD