One of the hottest
topics worldwide right now is the human diet, but the problem is that there are
so many opinions on what the ideal human diet should be, that it’s almost
impossible to know which one to follow. What we do know is that diet has a
direct effect on both mental and physical health. Inappropriate diets have been
shown to lead to undesirable diseases such as type 2 diabetes or even cancer.
Recent research has lead many people to believe that a plant-based diet may be
the answer to the worlds growing diet dilemma.
It is often debated
whether humans should be meat eaters or not – from our teeth (with a lack of
true canines as found in carnivores) to our gut (which is similar to that of
apes, who survive on a diet of fruit, leaves, nuts, insects and the occasional
scrap of meat as opposed to that of bears, who are true omnivores) all the
signs point towards a diet without meat. However, evolutionists have suggested
that without meat and animal products we may not have evolved as successfully
and speedily as we did. But the important question for us to consider now is
whether it is really necessary for us to continue to incorporate meat into our
diets?
Secret Number 1
In the world that we
live in today everything is much more accessible – and this includes
plant-based food sources that are high in protein such as nuts, seeds, quorn
and soy-based meat replacements. Iron can be sourced from legumes, grains, nuts
and a range of vegetables instead of from meat. Even Vitamin B12 can be sourced
from non-meat products such as cheese, eggs, milk and artificially fortified
products. This seemingly renders meat an unnecessary part of the diet as the
nutrients that meat is claimed to provide could be sources elsewhere. But does
this mean that we would be better off without meat? Or that it is simply
possible to meet nutritional needs without it?
Secret Number 2
When meat is cooked,
polycyclic aromatic hydrocarbons (PACs) are formed, and these are known to form
carcinogens when metabolised in the body. Carcinogens are molecules that cause
cancer. Cancer is a disease caused by an uncontrolled division of abnormal
cells in a part of the body – these abnormal cells are often the result of DNA
damage following checkpoint failures that are supposed to prevent cell division
progression if DNA is replicated incorrectly.
Secret Number 3
Meat is a high source
of N-nitroso compounds (NOC) and a form of iron (haem) that is not present
elsewhere, which increases the formation of endogenous NOC production. NOC are
carcinogenic; this has been confirmed in over 40 animal studies wherein NOC has
been found to produce tumours, as well as in case-control studies where higher
risk subjects were observed to have a greater exposure to endogenous NOC.
Secret Number 4
Furthermore, increased
non-haem iron from consumption of meat has been found to increase reactive
oxygen species (ROS). ROS increase the chances of DNA mutations through a high
rate of oxidation of the DNA bases. This may lead to increasing cell
proliferation in the large intestine if checkpoints fail to detect this DNA
damage. This is a possible mechanism explaining case-control studies with
findings that there is an increased risk of colorectal cancer with high intakes
of red and processed meat. The graph below is taken from Globocan (2002) and
shows evidence of this correlation.
Secret Number 5
There are many health
pros to the removal of meat from the diet. Studies such as Tai Le “beyond
meatless” have shown evidence that a plant-based diet has many health benefits
such as protection against cardiovascular disease, some cancers and total
motality. Vegan diets have been shown to further protect against obesity, type
2 diabetes, hypertension and cardiovascular mortality. Research, conducted by
Dr. Kahleova and published in the Nutrients
journal, has shown that in overweight people who adopted a vegan diet for 16
weeks there was an improvement in insulin sensitivity and beta cell function
compared to that of a control group. A large-scale meta-analysis reported that
there was a significant protective effect of a vegetarian diet against heart
disease and all cancers. In most cases a plant-based diet has been shown to
have preventative effects; however, there are also incidences of those already
diagnosed with diseases wherein the removal of meat from the diet was shown to
greatly aid in their treatment and recovery. In fact, people who were
chronically ill were found to reap even more benefits from plant-based diets than
those that were healthy. According to the NHS, in those with asthma it has been
found that eating cured or red meat over four times a week increased the risk
of having worsened asthma by 76%. Eating red and processed meats was also found
to increase the risk of depression by over 25% in a meta-analysis conducted by
Li Y et al’ published on PudMed, whilst fruit and vegetables were found to have
the opposite relationship. Animal products are not innocent either – it is said
that there is a 40% increased risk of death in breast cancer patients who drank
cows milk.
Recently, some doctors
have begun prescribing plant-based diets to patients to overcome many diseases,
or at least reduce their symptoms. An example of this is with rheumatoid arthritis.
The symptoms are believed to be relieved by reducing the patients exposure to
an inflammatory compound (Neu5GC) that is found in meat and animal products,
with evidence showing that the removal of meat in the diet has left sufferers
feeling better within weeks. Evidence supporting this arises from “The China
Study”, Campbell (2004), wherein it was shown that in countries with a lower
consumption of animal products there was also a lower incidence of rheumatoid
arthritis.
Secret Number 6
Meals incorporating meat have a tendency to lean towards unhealthiness. Steak and chips. Burger and chips. Cured meat platters. These are not well-rounded meals as in many cases they unfortunately do not contain any vegetables. Therefore it may be possible that the health benefits observed from switching to a plant-based diet may simply be the result of removing meat from the diet. It could follow that the benefits seen are the result of vegetarians (and especially vegans) needing to monitor what they eat to ensure that they are meeting all of their nutritional needs.
I spoke with a student at King’s College London, Zoe Cornish, who has been vegan since starting university. She told me that “Turning vegan definitely made me eat a lot healthier in general because it made me more aware of the ingredients in the foods I was eating, as well as making me conscious of the nutrients (or lack of) that I was gaining from them”. Zoe also added that although she sometimes struggles with eating out in restaurants located in quieter areas, switching to a plant-based diet gave her “more energy” and made her feel “less tired”.
Many case-control studies have shown that there is a decreased risk of colorectal cancer with an increased consumption of fruit and vegetables. It is thought that this is because of the dietary fibre, vitamins and minerals obtained from their consumption. Vitamin C and E, beta-carotene and selenium show antioxidant activity, acting to neutralise the reactive oxygen species that can damage DNA, resulting in mutations, which may lead to cancer development. Folate (also gained from fruit and vegetable consumption) is essential for DNA synthesis and methylation. It therefore seems that vegetarianism leading to an increased awareness of dietary consumption is equally as important as the decreased consumption of meat products in prevention of diseases such as cancer. However, it seems that red and processed meat must play a role in development of these diseases due to the presence of NOC and ROS following their metabolism and so it is not enough to simply increase fruit and vegetable consumption.
I know what you’re all thinking – how can I give up steak, burgers and lasagne?! Dr. William Kormos from Harvard Mens Health Watch has stated that there is a rise in the risk of disease with consumption of 50-100g of meat. But there is evidence that if you reduce your meat consumption by 50g per day, you will reap many of the health benefits of a plant-based diet. However, as the average UK citizen only consumes 17g of meat per day, this seems to show that most people would simply be better off without it. Just remember – just because the shops sell it, doesn’t mean we should eat it. Think about what you eat, whether it is meat or plant, diet is important!
Pictured are some meals that I have had recently - the majority are vegetarian, although I do eat chicken and fish from time to time.
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