Through all the research on diet and lifestyle of our early ancestors and into healthy indigenous and traditional cultures, one thing is now crystal clear.
There’s no ONE natural human diet.
Different parts of the world have hugely varied landscapes that grow different native foods and humans have adapted rather nicely to utilising on these available foods.
However what’s also clear is that although traditional diets varied hugely, the inclusion of at least some animal foods was essential to maintaining robust health over the long term.
There are no essential foods, but there are essential nutrients only found in animals foods. Plant-based diets are virtually devoid of B12, calcium, iron, zinc, the long-chain fatty acids EPA & DHA, and fat-soluble vitamins like A & D.
Adequate B12 intake is thought by some to be possible from certain plant sources such as seaweed, brewer’s yeast, spirulina and fermented soy. As it turns out, plant sources of B12 are mostly B12 analogues or cobamides which in fact block the intake of, and increase the requirement for true B12.
Vegans are often found to be deficient in calcium. Not just because their diet doesn’t include calcium rich animal foods but the calcium-rich plant foods they’re eating contain oxalates and phytates which block absorption of some of the calcium contained within them. (1) (2) (3)
Vegans often have lower serum ferritin concentrations than omnivores even though their iron intake calculations are comparable. Once again this is due to the form in which the iron is eaten. Many plant foods are high in iron but the iron is in the (non-heme) form that’s poorly absorbed. Many of these plant foods are high in iron absorption inhibitors, such as phytates, polyphenols and oxalates. The result of this combination is that 90% or more of the iron in those foods isn’t absorbed. Luckily the absorption inhibitors in only seem to apply to the non-heme sources of Iron, so If you’re eating plenty of veggies with your meat then you’re good to go. (4) (5) (6)
Zinc’s the same story, although there’s not too much concern about the intake levels of zinc in a vegan diet, the high levels of phytate in the plant foods being consumed increase the volume of those foods required to absorb sufficient zinc. (7) (8)
EPA and DHA are two (omega-3) essential fatty acids found nearly exclusively in fish and animal foods. These long chain fatty acids are thought to protect against diseases such as: cancer, asthma, depression, cardiovascular disease, ADHD, and autoimmune diseases. Some plant foods contain both linoleic acid (omega-6) and alpha-linolenic acid (omega-3) which are essential fatty acids. Some plant based omega-3 (ALA) can be converted into DHA and EPA however, the conversion rates are very low at about 5- 10%. The successful conversion of these ALA’s is dependent on adequate absorption of synergistic nutrients such as zinc and Iron – hmmm!
If we eat too many omega-6 fatty acids this will interfere with the successful conversion of ALA into DHA and EPA. This is why grass fed meats with a higher ratio of 3:6 are important. and why vegans who are eating diets high in omega-6 (which they inevitably are) are less likely to successfully convert ALA into EPA or DHA. (9) (10)
It’s been shown that traditional cultures all have a near equal balance of omega-3 and omega-6 in their diets.
As Nora explains in her wonderful article here’s a very special fat out there that is found only in the fat of grass-fed and finished animals. CLA or ‘conjugated linoleic acid’ could be one of the most healthful and potent cancer-fighting substances in our diet.
CLA has been proven to – even in amounts we’re likely to eat – can block all three stages of Cancer unlike most “anticancer nutrients” which are only effective in one stage. Research has demonstrated beneficial effects of natural CLA from animal fat have been found in cancers of the breast, prostate, colon and skin.
Correlation is not causation but it can give us clues. Several studies strongly suggest CLA could be particularly helpful in the fight against cancer. In one Finnish study, women who ate the most CLA had a 60 percent lower risk of breast cancer than those who ate the least. Some French researchers sampled the breast tissue of 360 women and found that the women with the most CLA had a staggering 74% lower risk of breast cancer than the women with the least CLA.
In a study that perfectly highlights the need for whole food solution not isolated nutrient supplements; human breast cancer cells were incubated in milk fat high in CLA or in an isolated form of CLA without any milk fat. The milk fat high in CLA decreased the growth of cancer by 90 percent compared to 60%. What was shocking is that some cells were incubated in linoleic acid (the omega-6 fat high in grain and grain-fed animals meat) the growth of the cancer cell increased by 25 percent!
There are more and more studies being done on the preventative properties of CLA against breast and Colon cancer and the findings offer a great deal of hope for those willing to source good grass fed and finished milk, butter and meat.
As Jo Robinson says on ‘Eat Wild’ ‘Many people take a synthetic version that is widely promoted as a diet aid and muscle builder. New research shows that the type of CLA in the pills may have some potentially serious side effects, including promoting insulin resistance, raising glucose levels, and reducing HDL (good) cholesterol.’ You just can’t fake natures processes.
Vegan diets are nearly entirely absent in fat soluble vitamins A and D. Fat-soluble vitamins are critical activators to human health and are found mainly in animal foods particularly seafood, organ meats, eggs and dairy.
Vitamin A has a critical role in maintaining healthy vision, neurological function and healthy skin.
Vitamin D deficiency is common and linked to increased risks of developing common cancers, autoimmune diseases, hypertension, and some infectious disease.
Apart from certain hard to find mushrooms which contain vitamin D, most plant foods don’t contain vitamin A or D. Plants contain beta-carotene which is the precursor to vitamin A but the conversion rates are poor. (12) (13) (14)
Vitamin D levels have been shown to be 74% lower in Vegans than in Omnivores.
To get the same vitamin A hot as a portion of beef liver you would have to eat 14 cups of carrots. We know that in healthy traditional cultures people at up to ten times the amount of Vitamin A than our current RDA. To attain these levels of vitamin A today from plant sources would be virtually impossible. (15) (16)
In 1945 Weston A Price discovered through the chemical testing of the organ meats, eggs and butter eaten by healthy traditional cultures an unknown fat soluble nutrient he called ‘Activator X.’ He discovered that the nutrient was present in higher quantities in the meat, milk, butter and eggs of animals eating quickly growing green plants in healthy pastures.
Dr Price found the nutrient played an influential role in the absorption of minerals, protection from tooth decay, growth and development, protection from disease and the healthy functioning of the brain.
A growing body of scientific work now confirms that the mysterious activator was Vitamin K2 which work synergistically with the other fat soluble activators vitamins A and D and is usually conveniently packaged with them in traditional fatty grass fed animal foods. (17)
Vitamins A and D tell the cells to produce certain proteins and vitamin K then activates these proteins. The K vitamins are also essential for effective blood clotting.
As illustrated in Kate Rheaume-Bleues’ ,‘The Calcium paradox’, vitamin K2 is the transport mechanism that gets calcium to your bones and eating calcium without sufficient K2 will be essentially wasted. Supplementing calcium could even be harmful in the absence of animal foods as it could increase the formation of plaque in the arteries or kidney stones if it’s not utilised in the bones.
Apart from fermented soya ‘natto’ and some other fermented vegetables, plants don’t provide vitamin K2. The K2 found in fermented foods is produced by the bacteria (animals) in the fermenting process. The K1 found in green leafy vegetables has a low conversion rate when ingested directly by humans – approximately 10% .
Vitamin K2 is thought to be one of the main nutrients responsible for the wide facial structures, lack of tooth decay and fine stature of the non-civilised people Weston Price studied in his research.
Weston Price found that ‘the diets of healthy, non-industrialised peoples contain at least four times the minerals and water-soluble vitamins, and ten times the fat-soluble vitamins found in animal fats (vitamin A, vitamin D and Activator X, now thought to be vitamin K2) as the average American diet.’ (18)
Modern diets in ‘civilised’ parts of the world are now based on processed foods, refined grains, sugars and vegetable oils. But even the animal foods we are eating contain only a shadow of the nutrients our ancestor’s wild meats would have offered up.
In one study Cows grazing pasture and receiving no supplemental feed had 500% more conjugated linoleic acid in milk fat than cows fed typical dairy diets. (19)
In another study, fatty acid profiles were significantly modified by different diets in milk cows. CLA, vaccenic acid (VA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) significantly (P < 0.05) increased in plasma as a function of the proportion of pasture added to the diet. (20)
In a study on lamb by Bristol University the favourable fatty acid profiles of lamb improved when lambs where grazed on habitats with a greater diversity of species against a control of lowland pasture.
It’s clear from numerous studies that animals eating a natural diet with produce meat, milk and eggs that are higher in many of the nutrients helpful to human health. It is also clear that the health of the land, diversity of the habitat and breed or species of the animal influences the potential health and therefore the produce it supplies. Choosing produce from animals that have been reared in ways that mimic nature will outperform those which have been reared on un-natural foods in confinement every time.
I need no convincing that a diet high in poor quality and processed animal proteins is bad for your health and I would also like to make it clear that I’m not necessarily suggesting a high-protein diet is a great idea either, especially it reduces the amount of nutrient dense veggies you eat. Individual health, associated eating habits, quality of food choices, hormones, common gene mutations and the composition of our gut microbiome are hugely influential on how successfully we utilise and convert nutrients. Some people will manage very well on a vegetarian diet who others will feel and look terrible. A vegetarian diet based on junk food is a very different deal to a raw food diet which includes pastured eggs and raw milk. We need to be careful about jumping on a bandwagon or making sweeping statements. (21)
That said there’s no credible evidence that being a vegetarian is any healthier than being a health-conscious omnivore. (22)
There are many studies being thrown around to ‘prove’ a vegetarian diet results in better health but in nearly all of them they are loaded with what is known as the ‘healthy user bias.’ The healthy user bias occurs because the type of people who would take a huge step like cutting out an entire food group from their diet in the name of improving their health, are already some of the most health oriented and ethically minded people within society. (23)
To compare vegetarians with a general selection of meat eaters which includes a considerable number of McDonalds eating and sugar addicted elements of society is a tad unfair! But even with a fair heap of healthy user bias included, this study found no difference in mortality rates between vegetarians and meat eaters in the UK. (24)
Here’s an example of why these types of studies don’t prove cause:
This study compared smokers with non-smokers and analysed their consumption of vegetables and other healthy habits.
‘Although Americans as a whole have unhealthy diets, smokers appear to have worse diets than their nonsmoking counterparts. Prior epidemiological studies have shown that smokers consume more fats, alcohol, and caffeine and less fruit, vegetables, and fiber than nonsmokers.5–7 These unhealthy habits are evident even among adolescent smokers. Teenage smokers are more likely to skip meals8,9 and eat less healthy foods10 than their nonsmoking counterparts’.
From this study, you could conclude that smoking somehow stops you eating vegetables. The more sensible conclusion, however, is that people who smoke aren’t educated in healthy eating choices or don’t give a hoot about their health.
Thankfully there is one study that does consider this healthy user bias. This study compared omnivores and vegetarians that both shopped in health food stores and found no significant differences in rates of mortality even though vegetarians are likely to be consuming far higher amounts of nutrient dense vegetables.
This study also studied omnivores and vegetarians that were considered healthier than the average population and found no statistically significant differences in rates of mortality.
Being a healthy vegetarian seems to be as achievable as being a healthy omnivore, but remaining healthy as a vegan for a prolonged period is a far harder task. Vegans need to supplement heavily and there’s little room for ‘empty’ calories; every mouthful should contribute towards a carefully planned nutritional plan that fills all the gaps.
Be aware that we have no historic evidence of any healthy cultures that didn’t eat at least some animal foods, nor do we have any long-term evidence of vegans that have maintained robust health for more than one generation. If you choose to follow this diet you’re part of a rather uncertain human experiment!
I would love to hear your thoughts on ‘Are you missing out? The potential nutrient deficiencies of a vegan diet’ below.
For many more links to relevant research and evidence please take a look at the ‘healthy Omnivore‘ board.