Promoting the value of meat in the human diet

In the last 10 years, considerable efforts have been made to reduce the amount of animal proteins in the human diet, commented Professor Alice Stanton when she presented at the Bord Bia meat marketing seminar held recently. The Royal College of Surgeons of Ireland (RCSI)-based clinician/scientist provided firm evidence on the benefits and positive health outcomes from eating a broad-based diet including meat as an essential element of that diet.
Professor Stanton elaborated on her comment by saying that a move away from meat consumption would not be in the best interests of the human population: “A dramatic reduction in animal-sourced foods including meat, would result in micronutrient deficiencies. Important nutrient deficiencies would accrue, including in terms of iron, zinc, iodine, vitamin D, vitamin A and protein. All of those are either best got from animal-sourced foods such as meat or are only got from animal-sourced foods. That last observation refers especially to vitamin B12, which only comes from animal-sourced foods.”

A balanced approach

Asked about the general diktat that we should eat less meat, Professor Stanton said that a balanced diet is what should be followed: “A reasonable guideline is one-third of calories, which, visually would equate to a quarter of your food coming from animal-sourced foods, including meat, dairy, fish, eggs, and that is a balanced diet. The remainder should come in large part from unprocessed fruit, vegetables, and wholegrains.”
In examining the contradictions contained in some statements around reductions in meat or animal-based food sources, she said: “Statistics can hide huge divergences in diet and nutrition and food requirements. In low-income countries and in low-income families within the developed world, people often eat a lower quality diet, both in terms of protein and micronutrients, and in terms of fresh foods. As a general overview, what we need to be doing is promoting and ensuring that there is an equitable distribution of high quality, nutritious food from a variety of sources and food categories.”

The benefits of meat

Asked whether there are significant differences between various red and white meats, Professor Stanton remarked that both categories have similarities: “Both are high in protein and are high in micronutrients including vitamin B12, and vitamin D. Red meat,  because it has more haem iron, is richer for iron and provides, in fact, a more bioavailable form of iron. That means that when it is eaten, the iron gets more easily into the human body. There are similarities and some subtle differences between the red meats, including beef, pork and sheepmeat, and the white meats sourced from poultry. Eating a wide range of animal-sourced foods as well as a wide range of plant-sourced foods are the definition of a balanced diet. It’s not just about eating red meat and just eating oranges as your fruit. Actually, you are better off with a range of colours – a rainbow of colours – both from plant and animal-sourced foods.”

Vegan diet challenges

Professor Stanton was asked whether a vegan or vegetarian-based diet can be supplemented to ensure a healthy diet: “It is theoretically possible to make up the deficiencies with supplements. The problem is that we only measure about 20 vitamins and minerals. There are hundreds, if not thousands, of bioactive chemicals, which usually travel along with those measured vitamins and minerals. So, while one could adopt a vegan-based diet, and procure enough iron, zinc, and vitamin D from supplements, there would be variations in bioavailability. What I would be most concerned about are other unmeasured beneficial chemicals that accrue from eating whole foods. In addition, if you are adopting a vegan or vegetarian diet, you need to know what you are doing, because plant-based protein quite often is missing some essential amino acids.
“So, you need to actually have a mixture of plant-based protein-rich foods in order to achieve balance; likewise, with vitamins and minerals. That takes effort and time, which are not necessarily available in modern society. It would be difficult for a family with two working parents to actually source all of the necessary ingredients and cook all of the ingredients in order to have a balanced diet for their whole family, when they are so time-poor,” she said.

Complex micronutrient interactions

Professor Stanton discussed the interactions between various micronutrients that are not replicated through supplementing vegetable-based diets: “We measure about 20 of those micronutrients or chemicals within food. But of equally significant importance is how the food is made up–the food matrix, if you want a scientific description. When food is in that integrated form, that influences how the gut responds to it and how well the food is absorbed.”
In a previous presentation to the Oxford Farming Conference, Professor Stanton had been critical of some of the assumptions of the EAT-Lancet Commission’s Reference Diet, which promoted a 90 per cent reduction in red and processed meats. Reiterating that criticism at the Bord Bia event, she stated that such a strategy would not save many lives and would result in ‘greater deficiencies in iron, omega-3-PUFAs, (polyunsaturated fatty acids), calcium, vitamins D and B12 and protein, with disproportionate effects on women and children’.

Decreasing nutrient values 

Another notable, even somewhat alarming, set of statistics presented at that Oxford Farming Conference six years ago referenced the reductions in nutrient content of fruit and vegetables over a 50-year period as confirmed in a US study of nutritional data from both 1950 and 1999 for 43 different vegetables and fruits. The differences were so large as to be statistically significant. Across the range of fruits and vegetables, protein content had reduced by 6 per cent. Calcium levels were down by 16 per cent, with a reduction in phosphorous content of the same magnitude. Iron content had reduced by 15 per cent, and the reductions in riboflavin and vitamin C content were quite extraordinary, at 38 per cent and 20 per cent, respectively.
The reasons, agronomic or otherwise, for these reductions were not elaborated on, but a rational deduction would be that greater intensity of production, higher yielding, potentially less nutritious varieties, and more intensive, shorter growing periods between planting and harvesting, could all have contributed to lower nutrient values.
Assuming that these reductions in fruit and vegetable nutrient values have not been reversed, and may have deteriorated further in the last two and a half decades, the need to pursue a balanced diet, made up of all the food sources available for healthy human nutrition, including meat, is more critically important than ever.