The longstanding argument of a vegetarian versus a non-vegetarian diet revolves around more reasons than one. This article, however, focuses on the advantages of each based on the kind of the protein they deliver, and their bearing on our health status.
There are three main factors to consider when picking a protein source. Here’s a look at them, along with how both animal and plant protein fall into each.
1] The Amino Acids It Provides
Proteins are made up of amino acids, all of which aren’t equal; we need an assortment of them, since they all serve different purposes.
Some of these amino acids can be made by our body, while others can’t. The latter, called ‘essential amino acids’ or EAAs, need to be obtained from our diet in order to fulfil various requirements of the body; for example, an EAA called ‘leucine’ is needed by our body for its post-workout muscle-building process, while another one called ‘tryptophan’ is needed for the production of serotonin, the hormone that creates feelings of wellbeing and happiness.1, 2
The primary difference between animal and plant proteins is their amino acid profiles, i.e., the kinds of amino acids they deliver.
Since animal proteins are comparatively similar to us, they tend to deliver all the amino acids we need.
Certain EAAs from animal protein (especially a certain group that leucine belongs to, called ‘branched chain amino acids’) increase our lean muscle mass, which increases our metabolic rate, and helps with weight loss. Eggs and whey (a protein from milk) are particularly rich in these, which is why they’re so popular among fitness enthusiasts.3, 4
Plant proteins often lack one or more EEAs – but turning to different sources of plant protein can make up for the deficit. For example, legumes provide the amino acid called ‘lysine’, which is low in many grains, while grains provide ‘methionine’, which is low in legumes. That’s why vegetarians are encouraged to include a variety of protein sources in their daily diet.5, 6
2] The Amount of Protein Put to Use by Our Body
The differences in the amino acid profiles between plant and animal sources even govern how much of their protein content is used.
Because of the similarity between our proteins and those of animals’, eating animal sources of protein gives us amino acids in the proportions we need. That’s why animal-based protein sources, including dairy, eggs, and meat, are highly digestible or have a high biological value of over 90%, which is the percentage that can be absorbed by our body and put towards making the proteins our body needs.7
Protein from sources such as oats, maize, beans, peas, and potatoes tend to be less easily digestible than animal-based protein, with biological values ranging from 45% to 80%. This is because of the presence of anti-nutrients (compounds that block the absorption of other nutrients), which, in some cases, can be reduced by the method of preparation.7
However, when extracted from the source, the biological value of plant-based proteins becomes similar to that of animal-based protein. This is found in the form of protein supplements such as soy protein isolate, pea protein concentrate, and wheat gluten. Protein in this form is especially helpful for vegans who may not always meet the recommended amount of protein in their diet.8
3] The Other Nutrients in the Sources
Diets high in plant protein (diets with over 50% of their protein coming from plant sources) are associated with a better status of cholesterol, blood pressure and blood sugar levels.9-12
This is potentially due to the plants’ high amount of phytonutrients, i.e., health-promoting compounds (such as antioxidants that fight free radical damage).9-12
Animal protein foods have some accompanying health benefits, too. For example, fish is a rich source of omega-3 fatty acids, and consuming it regularly has been linked to a reduced risk of heart disease.13
Generally found in eggs, fish and meats, vitamin B12 is often deficient in a vegetarian diet. The cells in our body, especially those in the brain and nervous system, require B12 to function.14 Eggs are also an excellent source of almost all the nutrients we need, and are therefore considered a superior protein-containing food.3, 4
Concerns Regarding Animal and Plant Protein
While we consider the amino acids profile and health benefits of protein sources, the other nutrients and compounds that come along with the protein (which may not always be good for us) should also be kept in mind, since this protein package is also likely to make a difference to our general health.
Here are some things to look out for:
1] Processed Meat:
Processed meat isn’t considered good quality protein because its compounds, which aren’t generally found in fresh meat, can be harmful to our health. This applies to meat that has been salted, smoked, cured, dried or canned, and includes hot dogs, sausages, salami, bacon and ham.15, 16
2] Factory Farmed Animal Products:
Another concern with commercially available meat is that factory farmed animal products may have remnants of the hormones and antibiotics given to the animals. Whether their quantity is enough to make a significant difference to our health is still a matter of debate.
3] Lactose Intolerance:
Milk has a sugar called lactose, which doesn’t suit everyone. There is an extremely high incidence of lactose intolerance in India, and the overlap of its symptoms with other gastrointestinal issues makes it difficult to identify. If you regularly consume dairy products and frequently experience gastrointestinal issues, getting tested for lactose intolerance might be useful. Those who are lactose intolerant would be better off opting for a whey protein isolate (which has almost all the lactose removed) or a plant protein.17, 18
Plant protein tends to give us a high amount of carbs (quantities of which often need to be controlled) so, when increasing its consumption, it’s important to simultaneously reduce the quantity of carb-rich foods (like baked goods).
The evidence clearly suggests that both sources of protein offer their own set of great health benefits.
Based on what we currently know, a diet that’s rich in plant protein and also includes some high-quality animal-based protein seems to be the best combination for optimal health.
An interesting note for fitness enthusiasts: one study suggested that mixing soy with whey protein might actually help our muscles use the amino acids more efficiently, by perhaps slowing down the absorption of the whey by the body and giving our muscles a longer time to use the amino acids while recovering.19
Those who prefer following a vegetarian or vegan diet and find it difficult to get a sufficient amount of protein through food, can turn to protein supplements as well.
As with most things in nutrition, balance is the key; it’s best to keep your diet nutrient-rich by including protein-containing foods from various sources.
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