I teach a first year compulsory nutrition paper – on two campuses. I introduce the macronutrient and micronutrient functions, the food and nutrition guidelines and the main public health issues around nutrition and health. People often ask me how I deal with teaching the students guidelines and recommendations that I don’t fully endorse. For the most part it’s not a problem. This is a university environment. The students are adults now – or need to practice being adults. I tell them at the start of the course that it’s the nature of the paper to teach them what the recommendations are – if these change, then obviously the base content will change. I then go on to tell them that, in this environment, it is their responsibility to challenge and question what they hear. Far from avoiding it, we encourage their insights and discussion. University is about nurturing critical thinking, not rote learning.
Last week we covered the Food and Nutrition Guidelines. This week it was micronutrients. As I was standing up there, discussing the benefits of vitamins A, D, E, K, and the best food sources for each, there was no better illustration of the conflicting messages that exist within our food guidance systems. In the Food and Nutrition Guidelines we are recommended to choose low fat dairy products. However, with the fat soluble vitamins, of which dairy products are a great source for vits A, D and K, it’s far more beneficial to consume in the presence of fat to maximise absorption. In addition, increasing evidence is pointing to the benefits of dairy that extend beyond the delivery of calcium and vitamins, and that the fatty acids present in the dairy fat could well be protective against weight gain, cardiovascular disease, diabetes and some cancers.
A Swedish study over 12 years found men who ate full fat milk, butter and included cream dairy products were less likely to be obese than those who avoided it, and (in combination with a high intake of fruit and vegetables) was protective against coronary events. In another, there was a reduced risk of colorectal cancer with the consumption of more than four serves of full fat dairy among 60,000 middle aged women, compared to those with the lowest intake. In adolescents, there was no association between full fat milk and obesity, and in fact it was skim and 1% milk that was associated with weight gain. In fact, this meta-analysis of 16 papers found that 11 of them reported beneficial effects of consuming full fat dairy products on obesity and metabolic health outcomes.
Interestingly, the research showed association between dairy fat and health is much stronger in European countries than it is in the US. When it was investigated, the researchers found a large proportion of dairy fat is consumed in the US was in the form of more processed food choices, such as ice cream and pizza. Europe retains a stronger tradition of consuming full-fat traditional dairy products such as plain cheeses, plain butter, and unsweetened yogurt.Another difference between Europe and US is the quality of dairy fat present in the foods. Typical dairy farming in the United States is highly industrialised, with a focus on maximising yield per dairy cow. Among other things, cows are treated with growth hormones, and the cows are not as likely to be pasture fed, relying instead on corn and soybean-based feed concentrates. Thankfully for us in NZ, we are less industrialised, where cows are (more often than not) grass fed.
So what makes full-fat dairy beneficial? For one, the increased fat in the dairy products will naturally be more satisfying – thus potentially help with regulating food intake more than the skim or trim milk options (higher in protein and carbohydrate) would give. Science is also pointing to the fatty acid composition. Dairy fat is a rich source of butyric acid (C4:0), a short-chain fatty acid that, for the most part, is produced in our gastrointestinal tract. I’ve talked about butyrate before in relation to resistant starch and our gut health. It’s extremely beneficial for our immune system and in a small clinical study, 4g daily of oral butyrate over 8 weeks reduced inflammation in the gastrointestinal mucosa and improved Crohn’s disease symptoms.
Full-fat dairy products also contain conjugated linoleic acid (CLA). This is a naturally occurring trans fat which has been found to be beneficial in health. Unlike industrial trans fats found in many processed foods that are well established to be harmful, the structure of natural trans fats has been found to be reduce risk of heart disease, diabetes and cancer found in population based studies. Animal models have found a reduced plaque formation in the arteries in rats and it also seems CLA is associated with better control of insulin in the body, thereby reducing risk of diabetes.
So then, what of the message to ‘choose low fat dairy products’ that is part of our Food and Nutrition Guidelines? Ignore it. While that might ruffle some feathers, our guidelines were set over 10 years ago and therefore much of this research I’ve included is more recent than that. A review of these guidelines can’t be too far off and (fingers crossed) they will be founded on an evidence-base that includes this relevant and important information. Hats off to Brazil. Not just good at football, they have recently launched their new food and nutrition guidelines and there is nothing whatsoever controversial about these:
The guide’s three “golden rules:
- Make foods and freshly prepared dishes and meals the basis of your diet.
- Be sure oils, fats, sugar and salt are used in moderation in culinary preparations.
- Limit the intake of ready-to-consume products and avoid those that are ultra-processed.
The ten Brazilian guidelines:
- Prepare meals from staple and fresh foods.
- Use oils, fats, sugar and salt in moderation.
- Limit consumption of ready-to-consume food and drink products
- Eat regular meals, paying attention, and in appropriate environments.
- Eat in company whenever possible.
- Buy food at places that offer varieties of fresh foods. Avoid those that mainly sell products ready for consumption.
- Develop, practice, share and enjoy your skills in food preparation and cooking.
- Plan your time to give meals and eating proper time and space.
- When you eat out, choose restaurants that serve freshly made dishes and meals. Avoid fast food chains.
- Be critical of the commercial advertisement of food products.
Now doesn’t that just make sense? I’m sure that, regardless of what ‘nutrition camp’ you sit in, most would agree that New Zealand should take a leaf out of this book.