BIOAVAILABILITY OF MICRONUTRIENTS

Veganism: Plant diet putting you at risk

Plant foods should complement, rather than compete with animal foods.

In Summary
  • Common vegan deficiencies include omega 3 fatty acids, magnesium, vitamin B12, vitamin D3, Iron, Vitamin B6, vitamin K2 and zinc.
  • Animal foods, by far, contain the highest concentration of vitamin A.
A crispy falafel bowl.
A crispy falafel bowl.
Image: @treatske

I'm not just pro red meat. I'm pro all animal-based foods. Meat, eggs and fish contain all the nutrients we need, and importantly, in their most accessible (bio-available) form.

Last week we learned that the small size of our colons (large intestine) precludes the sheer numbers of bacteria that would be required to effectively ferment high-volume fibrous plant foods. What is undisputed is the fact that humans must have some form of concentrated (high-quality, animal-sourced) nutrition in order to thrive.

Animal-based foods are incomparably nutritious. Strict vegan diets often lack sufficient quantities of essential vitamins and minerals (micronutrients).

Individual plants are nutritionally insufficient, and the available nutrients are often not easily bio-available. Therefore, a variety of plants must be consumed, and often in fairly large quantities.

 
 

Common vegan deficiencies include omega 3 fatty acids, magnesium, vitamin B12, vitamin D3, Iron, Vitamin B6, vitamin K2 and zinc.

Plant and animal proteins differ in bioavailability and amino acid content. Animal proteins contain all the amino acids not produced by the human body (the 9 essential amino acids). Meat, fish, and eggs are complete proteins, in that they contain an adequate proportion of each of these essential amino acids.

There are also plenty of vegan/vegetarian protein sources such as lentils, hummus, nuts and seeds, and whole-grain foods. Legumes and cereals can be combined to provide all of the essential amino acids for complete proteins.

VEGAN DIET

I acknowledge that a carefully designed vegan diet is incomparably better than an ultra-highly processed diet, packed with sugar, refined flour, and industrial seed oils. These diets make people sick and fat, regardless of whether they are vegans, vegetarians, or meat-eaters.

Bioavailability of micronutrients is a very important, yet often overlooked concept. In this concluding part of my series on veganism, I explain its importance by highlighting a few examples.

Retinol, the major (direct) form of vitamin A, is found in foods of animal origin such as meat, egg yolks, dairy, and fish.

The vitamin A found in orange and green vegetables is beta-carotene (pro-vitamin A). The body does not absorb pro-vitamins as efficiently as it does retinol. This indirect form of vitamin A must be converted into retinol (using enzymes) to be of any value to the body. This is an inefficient, energy-consuming process.

Animal foods, by far, contain the highest concentration of vitamin A. Since our bodies are not as effective in extracting vitamin A from plants, a diet that excludes all animal-based products could set the scene for a vitamin A deficiency. In addition, being a fat-soluble vitamin, vitamin A’s absorption is greatly enhanced when ingested with fat – fat which just so happens to be abundant in animal foods. That is no coincidence.

Vitamin B12 is one of eight B-vitamins. Dietary deficiency is very rare in developed countries due to access to meat and fortified foods. It is synthesised by certain species of gut bacteria in humans and animals. Humans, unlike ruminants, cannot absorb it, as our fermentation occurs in the large intestine and absorption higher up in the small intestine. We, therefore, derive the vitamin B12 we need from animal foods, particularly, organ meats, poultry, fish and insects.

 

Vegans are at risk of B12 deficiency, which can cause a variety of initially vague and later potentially serious complications.

DIET SUPPLEMENTS

There is also no doubt that a non-supplemented vegan diet is inferior, nutritionally, to an omnivorous diet. A diet which necessitates supplementation with vitamins A, D, K, B12, omega 3 and iron, is neither natural nor advisable.

 

Omega-3 fatty acids are essential fats that have a wide range of health benefits, including reducing inflammation and decreasing blood triglycerides (fats).

The best sources of omega-3 fatty acids include fish oil and fatty fish like mackerel, dried sardines (omena), and salmon.

The three most important Omega 3’s are EPA, DHA, and ALA. ALA (alpha-linoleic acid) is mostly found in plants, while EPA and DHA are mostly found in animal foods like fatty fish.

For ALA to be useful to the body, it must first be converted to EPA or DHA. This conversion is limited and inefficient, with only about 5% of ALA being converted to EPA, while less than 0.5% is converted to DHA.

Vegans would need to supplement EPA and DHA with vegan-friendly supplements to meet their omega-3 needs

I acknowledge that a carefully designed vegan diet is incomparably better than an ultra-highly processed diet, packed with sugar, refined flour, and industrial seed oils. These diets make people sick and fat, regardless of whether they are vegans, vegetarians, or meat-eaters.

There is also no doubt that a non-supplemented vegan diet is inferior, nutritionally, to an omnivorous diet. A diet which necessitates supplementation with vitamins A, D, K, B12, omega 3 and iron, is neither natural nor advisable.

I respectfully refuse, therefore, to accept the vegan nutrition argument. It is for this reason that I often emphasise that plant foods should be seen as complementing, rather than competing with animal foods.

UK-based consultant physician and obesity management expert

www.insulean.co.uk/[email protected]/Facebook: Nyambura Mburu Svendsen, or @insuleanmedical