Interview with Dr Tim Crowe
Raise a glass to regular fat milk!
To say we eat whole foods, not nutrients is stating the obvious. Yet this premise is driving a growing body of nutrition research that is shifting our understanding of how whole foods affect our health.
Recently we have seen the Heart Foundation review the current science in relation to dairy and heart health, with their findings coming as a surprise to many practitioners. Based on contemporary evidence, the Heart Foundation now recommends both regular or reduced fat milk, cheese and yoghurt, as part of a heart healthy eating pattern for the general population.
Dr Tim Crowe is a nutrition research scientist and a member of the Expert Reference Group that assisted in development of the Heart Foundation’s ‘Dairy & Heart Healthy Eating’ dietary position statement. We spoke to Dr Crowe to provide some further insights into the science behind these new recommendations and the implications for general practice.
Tim, for many years we have been told that saturated fat is ‘bad’ for heart health and now the Heart Foundation is recommending regular fat dairy foods. Can you explain this shift in thinking?
Nutrition science is undergoing a seismic shift. What was before a mostly nutrient-focus has now shifted to be much more food-focused with the study of how foods, as part of a whole diet, interact with each other to affect our health. And this is no better illustrated with the recent shift in the position of the Heart Foundation on its advice on dairy.
A key change by the Heart Foundation is to more strongly promote eating a variety of healthy foods rather than fixate on one specific food or nutrient. A good example is the evidence base for the relationship between dairy foods (milk, cheese and yoghurt) and cardiovascular health. On balance, the evidence suggests a neutral relationship, and even a possible protective relationship, between dairy foods and hypertension, stroke and type 2 diabetes risk
For healthy people, the previous recommendation of choosing reduced fat dairy foods over regular fat has now been rescinded. Milk, yoghurt and cheese can be consumed as part of a heart-healthy eating pattern that includes vegetables, fruits, legumes, wholegrains, fish, olives, seeds, nuts and oils made from them.
For people who would benefit from LDL-cholesterol lowering dietary interventions, including those with elevated LDL-cholesterol and those with existing coronary heart disease, reduced fat and unflavoured products are still the preferred choices.
So, Tim in spite of its saturated fat and salt content, does this mean cheese is ‘back on the menu’?
The latest Heart Foundation Position Statement firmly places cheese back on the menu for the general population. Cheese is a good example of where the nutrient content of a food does not reliably predict its effect on health despite its fat content. This is because the calcium content of cheese may increase faecal fat excretion and is one possible explanation for why its saturated fat content does not correlate with a strong effect on LDL-cholesterol.
If we look at saturated fat in isolation, we know it raises LDL cholesterol. What is happening when saturated fat is housed within a whole food structure?
Saturated fat indeed raises cholesterol levels, particularly the more atherogenic LDL-cholesterol, but its effects are not consistent. Different foods are related to CVD risk in different ways and this is due to the food matrix effect. Like chocolate and potato chips, cheese and yoghurt also contain saturated fat – but there is a big difference in their nutritional content and food structure.
For dairy foods, fat exists not in isolation, but housed with various macro and micronutrients. In addition, milk fats are embedded within a complex structure called the milk fat globule membrane (MFGM). Emerging research is now linking the MFGM to brain development, immune function and gut health. The matrix can also modulate cholesterol uptake and is one possible mechanism that could explain a neutral effect of some forms of whole dairy foods on cardiovascular disease risk.
What are the implications of these new recommendations for clinical practice?
In clinical practice, the message to the general population is that regular or reduced fat milk, yoghurt and cheese can be enjoyed as part of a wider heart-healthy diet. For people with existing heart disease, dietary advice is to still favour reduced fat and unflavoured dairy foods. The Heart Foundation Position Statement on Dairy and Healthy Eating is the key resource for the full science and the thinking behind the change in dietary advice around dairy foods for cardiovascular health.
About Dr Tim Crowe
Dr Tim Crowe is a career nutrition research scientist, freelance health and medical writer and founder of thinkingnutrition.com.au. To hear more from Tim and the latest in nutrition research search for the Thinking Nutrition podcast in your favourite podcast app.
