Proteins are a part of the seven classes of food as learnt in our elementary classes. They contribute to the food groups in numerous ways that help the body thrive and develop appropriately.
Of all the food groups, namely, carbohydrates, proteins, fats, vitamins, minerals, dietary fibres, and water, protein has gained a level of recognition in many facets of life including weight loss industry, sports, therapeutic and so on. This is based on their unique abilities in the body. In this article, we will be highlighting many of them and also enumerate certain ways to choose the best of proteins for our wellbeing.
What are proteins made from?
Proteins are made from amino acid build-ups. That is, they are formed when several amino acids join together to form a compound substance. Amino acids are referred to as the building blocks which forms protein structures. Little wonder why a protein is rated based on its amino acid composition.
There are 20 amino acids known which forms proteins when they are put together. They are further grouped into essential and non-essential amino acids which also depicts the relevance of the proteins they form when they are put together.
The World Health Organisation/ Food and Agriculture Organisation experts Consultation on Dietary Protein Quality Evaluation in Human Nutrition at a time suggested that the description of proteins should be based on the content of amino acids that are digested in them. When we look at this, we will then realise that they are taking each amino acid to be an individual nutrient since each of them would be digested at a different level or rate. In March 2013, the FAO then proposed and launched a protein quality score named the Digestible Indispensable Amino Acid Score (DIAAS) to that effect.
Functions of Proteins
Proteins are responsible for several actions and roles in the human body. Proteins are seen to support with growth and developments of the body from infancy up until adulthood.
Proteins are responsible for the repair and maintenance of injured or damaged tissues from our everyday works, stress, and actions. Their functions are seen in carrying out the roles of the reproductive systems, lactation, metabolic losses and so on.
Classifications of proteins
Just as carbohydrates are grouped into the refined and unrefined or whole forms, and the fats are also classified into saturated fatty acids, trans-fatty acids, mono-unsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), likewise, proteins are grouped.
Proteins are classified based on their origin or sources. They are classified into 2, namely
The plant sources like their name states are those proteins which are found in plants while the animal sources are those gotten from animals.
Plant and animal sources.
The protein foods as seen are chiefly of either the plant or animal origin, which makes them traceable to a source.
Plant proteins include legumes like beans, fava beans, soybeans, lentils, chickpeas, green peas, etc. Nuts of all types like the walnuts, groundnut, cashew nut, almond, chestnut, pistachios, etc.
Fruits and vegetables like, broccoli, avocado. Grains like wheat, rice, oats, maize, buckwheat, quinoa, etc.
Likewise, animal sources are meats, chicken, dairy, and eggs.
The protein sources as seen are chiefly of either the plant or animal sources, which makes them behave differently in the body. And based on their amino-acid components, they also possess a different influence on your overall health.
How much should I be eating?
On reeling out a recommendation on Protein intake, there has been a rise in the different board publications as regards how much protein is needed by the body.
The amount of protein needed by the body, just like every other macronutrient is dependent on the individual's physiologic circumstance. The gender, age, activity level of the individual determines how much protein will be required for their daily usage.
The recommended dietary allowance of protein by dietary guidelines for an adult is 0.8g per kg body weight of the individual. That is, a 70 kg individual should have up to 56g of proteins daily.
Yet, considering other factors of physical activity level and gender, some other boards have come out to put things in a broader range and perspective.
The Acceptable Macronutrient Distribution Range (AMDR) and MyPlate, have also proposed a range of values. the AMDR suggests a person can have between 1.05–3.67g of protein per body weight, and MyPlate recommends a range of 1.48–1.86 per kg body weight. All still putting into consideration the physiologic circumstances like age, activity levels, and gender.
A bodybuilder or heavy manual worker for example will require more protein in their food for adequate body repairs, muscle building, enzymatic functions and other healthy than a person who is mostly sedentary.
These recommendations allow for broader flexibility and planning of the personal meal beyond the 0.8g/kg body weight of protein quantity by the RDA for a normal individual. In other words, how much protein you will need is dependent on your individual needs, preference and or your body goals.
Now we know that there is an optimal level of protein intake that is often greater than what the RDA states.
Plant vs Animal Proteins
Over the years, there has been a heated battle as regards which protein source is more relevant and better. To answer this, I would love to say that putting this two sources side by side, we need to examine them nutrient for nutrient and get the one with the most influential nutrient on its sides.
For hundreds of years now, research has been revealing the pros and cons of these protein sources based on their bioavailability, digestibility, and even amino acid components in them.
However, while following research works, we need to be careful because the research works mostly are funded or sponsored. And the sponsor or funding will determine which way the research result will turn. Likewise, the statistics and subjects used for this study could be selectively chosen to suit their claim. Hence, in my findings and paper compilation, I made sure I looked at unbiased honest research works, those not funded by any food industry to avoid bias claims.
The perception and narration of plant protein have evolved over the years. Some researchers found that plant protein sources are not as bioavailable as their meat counterpart. While some also claim they are incomplete. An incomplete protein is when the food type does not have all essential amino acids in it. The rich animal agricultural industry has flooded the scientific body with heavy resources which makes research go in their favour. Poor plant foods.
The untrue narration about how you need to combine two or more plant foods to get a "balanced" protein quality has been debunked years ago also, as the initial research which was done hundreds of years ago was testing how well infant rats can grow on plant foods. It is like checking if they will grow on human breastmilk as well. It cannot be. Rats will not grow as fast as they will grow on plants or human milk because they are rats. Yet we cannot say human milk is incomplete in its growth components.
You do not need to combine plant sources to get adequate protein. Eating them in variations and combined forms only help you to make more protein available for your body's use. The American Heart Foundation confirmed this when they said the truth is, plant protein sources can provide enough of the essential and non-essential amino acids as long as the sources of the plant foods are eaten in variation. That is a unique thing the animal food also lacks_ variation.
Likewise, those who choose to eat plant protein options in their usual diet will not only have adequate protein content but also will have to worry less about meeting up to their calories expectations as well as fibre and other healthy micro nutrient contents. But like I mentioned earlier, the overall health impact is what we all should pay more attention to, as that is the reason why we should be choosing right food as well.
Which protein source best impacts my health?
Many animal and plant food sources have been seen to have different health effects. We will be looking at a number of them.
Over the years, there have been a series of studies that have shown the importance of having plant foods and how they tremendously benefit our body.
Although animal foods like meats, fish, chicken, etc., have been reported to rank higher in protein content, the presence of other nutrients in them which have adverse effects on the health is worth giving it the second thought.
However, it was until 2010 before the Dietary Guidelines Advisory Committee in the United States began to review the specific questions concerning the relationship between plant proteins and health. It was then that they decided to recommend that Americans have a switch of their food intake to a plant-based diet. With an emphasis on Wholefoods; grains, beans/legumes, nuts, seeds, fruits, vegetables, herbs and spices. This is something independent research works have been revealing years and years before then.
Plant proteins although was once seen as less nutritious or an incomplete source of amino acids, has now been rated highly as a healthy option for meeting protein needs or recommendations.
The fact that they are of plant origins, which also contain other whole food nutrients in themselves like carbohydrate, has been a reason why they are more identified as a healthy option.
In a Japanese study, it was discovered that because they ate more fish as their primary protein source, they had a reduced stroke rate than the United States where they ate more meats. Although populations that ate no animal food, just plant sources, had a far more reduced risk of stroke than those who ate both fish or meats.
Another study of normal-weight children from the age of 5 to 18 years whose parents were obese was made to eat 20% more protein foods. Their blood pressure and blood lipids which are cardiovascular risk marker were improved. This was in comparison with a 16% protein intake. This could mean eating more meat or meat products, but how risk aversive are meats?
Plant foods on a large note which is focused on legumes, grains, fruits and vegetables, have been found to greatly reduce risks of hypertension, obesity, cardiovascular diseases, stroke, Alzheimer's, and hormonal imbalances.
In a study of eighty-nine thousand Californians, plant-based eaters were compared with people who ate meat more than once a week, flexitarians (those who eat less meat, a few times in a month), those who eat only fish, those who cut out meats including fish, and those who ate no animal food or product whatsoever (meat, fish, eggs, or dairy).
Those flexitarians who ate meat more than once a week had a 23% lower rates of high blood pressure. There was a 38% reduced risk in those who ate only fish. Those who cut out all meats including fish experienced a 55% reduced risk of high blood pressure.
The best result was seen in participants who ate no animal foods or product whatsoever (meat, fish, eggs, or dairy).they had a 75% reduced risk of high blood pressure.
On a general note, having a diet which comprises of chiefly whole plant foods is associated with several health benefits such as a lower risk of death from heart disease, lower low-density lipoprotein (LDL) cholesterol levels, lower blood pressure, reduced risk of type 2 diabetes, lower body mass index, and lower rates of cancers.
Many believe that the excellent health benefits have been due to the beneficial nutrients like fibre, phytochemicals, minerals and vitamins present the whole foods (fruits, vegetables, whole grains, seeds, nuts, beans)
US Department of Agriculture and US Department of Health and Human Services. Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010. Washington (DC): USDA and US Department of Health and Human Services; 2010
Institute of Medicine of the National Academies. Dietary Reference Intakes for energy, carbohydrates, fiber, fat, protein and amino acids (macronutrients). Washington (DC): The National Academies Press; 2002/2005.
Plant Protein and Animal Proteins: Do They Differentially Affect Cardiovascular Disease Risk?
Chesney K Richter, Ann C Skulas-Ray, Catherine M Champagne, Penny M Kris-Etherton
Adv Nutr. 2015 Nov; 6(6): 712–728. Published online 2015 Nov 10. doi: 10.3945/an.115.009654
Damsgaard CT, Papadaki A, Jensen SM, Ritz C, Dalskov S-M, Hlavaty P, Saris WH, Martinez JA, Handjieva-Darlenska T, Anderson MR, et al. Higher protein diets consumed ad libitum improve cardiovascular risk markers in children of overweight parents from eight European countries. J Nutr 2013;143:810–7.
Fraser GE. Vegetarian diets: what do we know of their effects on common chronic diseases? Am J Clin Nutr. 2009;89(5):1607S–1612S.