ARE HUMANS MEANT TO BE VEGAN?
B12, lactose, herbivores and more...
Let's start off here - I'm not a nutritionist and have never been formally trained in nutrition. I'm only saying this because I know of a lot of bloggers and social media stars who have promoted certain diets and celebrated their incredible health benefits without any scientific foundation. However, I have tried my best to do some research and hell I'm even going to link my sources ver fancy.
(okay I've just looked up an article about whether humans are herbivores and the writer is getting slated in a comment for confusing vegetarianism/veganism (a lifestyle choice) with the genetic design of the human body. I am definitely not educated enough as to say whether humans are meant to be omnivores or herbivores. Within biology, humans are regarded as omnivores (Ley et al., 2008). I basically want to look at the argument that a plant based diet can lead to certain health benefits.) but is is all very interesting!!
NATURAL HERBIVORES?
A common myth is that humans are natural herbivores; we have to cook our meat to eat it, don't have the right teeth(very simply put we need bigger canines), meat consumption leads to heart disease, cancer etc.
In reality, humans can eat raw meat, but on a commercial scale it can be unsafe to do so. If you were to kill an animal and eat it immediately after, you shouldn't encounter any problems. It is that humans tend to store food before eating it later and this is when pathogens can grow and, if ingested, cause food poisoning. The structure of our teeth is part of our phenotype which is determined by evolution(the issue I said I'm not going into). And it is only the excessive consumption of meat in an unbalanced diet that can increase the risk of certain diseases.
BUT WE CAN'T MAKE OUR OWN B12?
One aspect of veganism I have always questioned is that vegans have to take B12 vitamin supplements. If we can only get B12 from animal products then doesn't that mean we're designed to eat meat? B12 is made by anaerobic microorganisms (bacteria that do not require oxygen to live). Anaerobic bacteria are common in the gastrointestinal tract of animals and can also be found in certain algaes [1]. Some herbivores, such as cows, get their B12 from bacterial contamination of their food. For humans this can often be unsafe so those following a plant-based diet choose to take supplements.
75% OF THE WORLD'S POPULATION ARE LACTOSE INTOLERANT?!
I recently read a statistic that 75% of the world's population are lactose intolerant. If you are lactose intolerant then you have a shortage of the lactase enzymes which break down lactose into its simpler forms, glucose and galactose. Virtually all babies have lactase enzymes hence why they are able to drink their mother's breast milk but the production of lactase eventually stops. About 75% of the world's population, including 25% of those in the USA, lose their lactase enzymes after weaning. Caucasians tolerate milk sugar only because of an inherited genetic mutation [2].
ARE VEGANS HEALTHIER?
A flaw we must keep in mind here is that some studies may mistake correlation for causality. Those who follow a vegan diet may be more likely to make healthier life choices which could then increase their life span and reduce their risk of certain diseases. So some studies may conclude that a vegan diet makes you live longer when in fact there is no way of knowing this was because of their diet or because they were more health-conscious and therefore, for example, exercised regularly. This may have been the case in a 2015 study which showed that those following a vegan diet lost comparatively more weight than those following omnivorous and vegetarian ones [5].
One study that has tried to avoid this mistake is the Adventist Health Study. The population studied, the Seventh Day Adventists, use almost no alcohol and tobacco and generally lead a uniformly healthy lifestyle. Half of the study were vegetarian and half ate small amounts of meat. It was found that the vegetarians lived longer than those who ate small amounts of meat, but other factors shown below actually had a larger effect on longevity than whether that person was vegetarian or near-vegetarian [3].
The study also found that eating nuts several times a week reduces the risk of heart attack by up to 50%.
Eating whole meal bread instead of white bread reduced non-fatal heart attack risk by 45%.
Drinking 5 or more glasses of water a day may reduce heart disease by 50%.
Of course this is only one study which has its own criticisms but it seems it can't be bad to make some small diet changes [4].
Another pro of veganism is that, in return, there would hopefully be less meat consumption. 27kg of CO2 is generated per kilo beef in comparison to 0.9kg per kilo of lentils [6]. According to a 2016 Oxford study, the adoption of a vegan diet globally would cut food-related emissions by 70pc [7].
These are some aspects of veganism that I find most interesting and potentially most controversial. It has been repeatedly proven that eating more fruit, vegetables, grains and pulses, therefore getting more fibre, nutrients and vitamins, can only be a good thing. As long as you take your B12, regardless or not if whether you think humans were designed to eat meat as we can't make the vitamin ourselves, the point is that now we can artificially manufacture it, there isn't much reason to continue animal farming.
SOURCES:
[1] http://nutritionstudies.org/12-questions-answered-regarding-vitamin-b12/
[2] http://www.pcrm.org/health/diets/vegdiets/what-is-lactose-intolerance
[3] https://www.nomeatathlete.com/b12-for-vegans/
[4] https://en.wikipedia.org/wiki/Adventist_Health_Studies (accessed 1/2/2018)
[5] https://www.ncbi.nlm.nih.gov/pubmed/25592014
[6] http://www.telegraph.co.uk/health-fitness/body/six-reasons-go-vegan-according-science/
[7] https://www.oxfordmartin.ox.ac.uk/news/201603_Plant_based_diets
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