It seems counter to many peoples perception that meat could be good for your health, many people see it as a good thing to reduce their meat consumption and move from red to white meats. As a vegetarian for 25 years my view on the health benefits of such a diet has changed, although this wasn’t my primary reason in taking up the diet, I can now see the advantage for me to include more animal protein in my diet. Here are some of those key reasons.
- The full set of 9 essential amino acids (the building blocks of proteins) are all present in animal products such as meat, fish and eggs. Where as plant sources of protein do not have adequate levels of some of the amino acids. In a plant based diet a combination of grain and legume is recommended to provide the best possible levels of amino acids. For me a recent test showed that I was indeed low in one amino acid, Lysine, which is often the case for vegetarians. (1)
- Vegetarian and vegan diets can lead to deficiencies in minerals. Grains, legumes and nuts have a high phytic acid content which has a strong binding affinity to important minerals, such as calcium, iron, and zinc, reducing their absorption. These minerals are more easily
absorbed from animal sources, red meats being particular rich sources of iron and zinc. (2)
- Usable vitamin B12 can only be found in animal products therefore it essential for Vegans to supplement this in their diet. It is indeed added to many vegan processed foods such as yeast extracts and milk substitutes.
- Fat soluble vitamins A and D can also only be obtained from animal sources, as fat is still vilified, this part is often removed, their presence among other roles assist in the assimilation of proteins. Beta carotene, found in dark green leafy and other vegetables can be converted to vitamin A, however it is now recognised that genetically many people have limitations in this conversion. (3)
- Plant proteins used abundantly in the diet can effect the gastrointestinal function due to the presence of lectins present in pulses and grains. Lectins are (glyco)proteins which affect the turnover and loss of gut epithelial cells, and interfere with nutrient digestion and absorption. (4) This however doesn’t always negate beneficial properties of plant proteins such as their fiber content, however adequate Vitamin A and Zinc are important to good gut health too, so you can start to see how a long term vegetarian diet could effect digestive health.
Studies that try to compare overall longevity of vegetarians versus carnivores are still hotly debated. The belief that meat is bad for you instantly causes a bias in the data, people who avoid meat have other healthy eating habits such as eating more fruit and vegetables, nuts and seeds. Whilst the meat eaters tend to be more sedentary and drink and smoke more. Making it very difficult to separate the confounding factors. Do vegetarians live longer? even data for this show no advantage when you look below the surface.
Many use the argument that we should eat as our ancestors did and hence the popularity of the “paleo” short for paleolithic diet. A diet based on Meat, Fish, eggs, Vegetables, fruit and some nuts and seeds. Of course the amount of animal products would have varied vastly depending on the location of our ancestor and perhaps more importantly what is actually available to us today give us a whole new set of choices
There are many Vegetarian iron men contenders and other athletes who seem to defy much of what I have stated and seem to model optimal health. There is no denying an often vegan sometimes raw diet can support the human body. They will be very aware of the above issues and tend to use protein powders and other extra supplements as well as a large amount of leafy greens and other vegetables. Using traditional ways of sprouting and fermenting grains and pulses can also reduce their anti-nutrient content. We soon see that this may not be for you, but it maybe its an individual’s choice. There are of course many other reasons to choose to be a vegetarian, understanding the nutrient difficulties in eating such as diet can allow someone to make informed choices. Knowledge is power.
The Vegetarian Myth by Lierre Keith
Nourishing Traditions: The Cookbook That Challenges Politically Correct Nutrition and the Diet Dictocrats by Sally Fallon
(1) Hung, C.J et al. (2002) Plasma homocysteine levels in Taiwanese vegetarians are higher than those of omnivores. Journal Nutrition 2002 Feb;132(2):152-8.
(2) Hunt, J.R. (2003) Bioavailability of iron, zinc, and other trace minerals from vegetarian diets, American Society for Clinical Nutrition
(3) Lietz, G. et .al (2012) Single nucleotide polymorphisms upstream from the β-carotene 15,15′-monoxygenase gene influence provitamin A conversion efficiency in female volunteers. J Nutr. 2012 Jan;142(1):161S-5S. doi: 10.3945/jn.111.140756. Epub 2011 Nov 23.
(4) Vasconcelos, I.M and Oliveira J.T. (2004) Antinutritional properties of plant lectins.Toxicon. Sep 15;44(4):385-403.