Why do we eat and how to do it right? – PART III
Welcome back! or maybe just welcome if you are here for the first time.
In the final part of the series “Why do we eat and how to do it right?”, we will learn about Protein, its functions in the human body, optimal sources of protein, how much do we need, and finally how the food we eat affects our mood. We will end with the series takeaway message. So let’s dive right into it!
Protein as a Macronutrient
Protein provides 4 calories per gram and is composed of “amino acids”. Amino Acids are organic compounds made of carbon, hydrogen, nitrogen, oxygen or sulfur, and are the building blocks of proteins.
There are 20 amino acids. 9 of those 20 are deemed as “essential”, meaning, we must get them through our diet as the body cannot produce them itself.
Functions of Protein
Protein is found throughout the body—in muscle, bone, skin, hair, and virtually every other body part or tissue.
When we think about Protein, the first thing that comes to mind is muscle mass. Yes, one of the functions of protein is to act as a building block for muscle mass, however, it is not the sole purpose of this nutrient.
Some other functions are as following:
Build and maintain Tissue: As mentioned, one of the functions of proteins in the body is to be used for the growth and maintenance of tissues. The body under normal circumstances breaks down the same amount of protein that it uses to build and tissues. In some cases, such as fighting an illness, during pregnancy, breastfeeding, or a period of high activity it can break more protein thus increasing protein intake needs.
Protein as enzymes: Enzymes in the body speed up chemical reactions such as digestion of carbohydrates or the synthesis of cholesterol by the liver. For e.g one enzyme most of you would have heard about is Lactase. which breaks down lactose in the milk and in the absence of which Lactose Intolerance takes place. Some proteins in the body act as enzymes and thus act as catalysts to the various necessary chemical reactions in the body.
Protein as hormones: Hormones are chemical messengers in the body that are released by the endocrine system (a complex network of glands). They carry messages to various parts of the body and help regulate various bodily processes such as hunger, blood pressure, and sexual desire.
For example, when we eat a meal, the pancreas produces the hormone “insulin” which helps regulate blood sugar by opening the cells to accept glucose from the blood. When we press the car brakes hard suddenly to avoid a collision, adrenal glands produce the hormone “adrenaline” to help us act quickly At night time (around 10 PM) our pineal gland produces the hormone “melatonin” which makes us sleepy and helps us get a night of restful sleep.
Many of the hormones are made from protein.
Proteins provide structure: Some proteins provide structure to the cells and tissues in the body. Keratin, for example, is a structural protein found in skin, hair, and nails. Collagen gives structure to bones, teeth, and skin.
Proteins as antibodies: Antibodies blood that helps in protecting us from harmful bacteria and viruses. Protein helps form these antibodies to fight infection.
Proteins as transporters: Some proteins act as transporters and help move nutrients such as vitamins/minerals, cholesterol, and oxygen. For example, hemoglobin is a protein that carries oxygen from the lungs to other body tissues.
Proteins as a backup source of energy: With so many important functions to perform with proteins, our body prefers to use glucose (from carbohydrates that we eat or make it from stored glycogen in the liver) or fats (ketones) for the energy. As a last resort, however, for example in case of longer fasting or starvation, the body can break-down muscle into amino acids and then make new glucose through a process called “gluconeogenesis”.
Sources of Protein
As we learned, protein is composed of amino acids and out of those 20 amino acids, there are 9 of them which are essential (our bodies cannot make them and we have to get it through food). Any food source which provides us with these 9 essential amino acids, is a source of “complete” protein, such as all animal sources (poultry, meats, dairy products), soy, and quinoa.
When it comes to plant-based sources of protein, what needs to be understood is that various plant-based foods are deficient in one or more amino acids. For example, beans and legumes have low amounts of amino acid “methionine”, and rice has low amounts of “lysine” and thus when combined together, rice and beans provide a “complete” protein profile. Moreover, we do not have to consume both at the same time. For example, having rice at lunch and beans at dinner will still provide the body with all essential amino acids to form protein.
So, animal sources have complete protein, some plant-based foods have complete protein (soy, quinoa) and some plant-based foods can be combined to form complete protein (such as grains with legumes – rice and beans, wheat and lentils, and nuts/seeds with grains – peanut butter sandwich).
However, as per the Harvard School of Public Health, it is not only the amount of protein in the source but also other nutrients that we get along that make a difference to our health.
For example, A 4-ounce ham steak has 22 grams of protein but also comes with 1500 mg of sodium. A cup of cooked lentils has about 18 grams of protein and also provides 15 grams of fiber.
Eating grass-fed meat would provide you a clean source of protein and eating processed meat will fill your body with chemicals and additives. So the source matters.
Many processed meats are loaded with salt, which can cause high blood pressure and lead to other health problems. Multiple studies show a link between consumption of red/processed meat and diseases such as cancer and diabetes.
Also, when it comes to animal protein sources, remember, you are not only what you “eat” but also what you eat “ate”. Meaning, if you are eating the meat of an animal who was fed GMO-corns and treated with antibiotics, indirectly you are ingesting those compounds too, which leads to inflammation in the body, the root cause of all chronic diseases!
Optimal Protein Sources
- Animal sources:
- Poultry: Opt for organic and free-range if possible.
- Meat: Opt for Grass-fed and Grass-finished.
- Dairy: Beware of added sugar and skip processed cheeses.
- Plant-based sources:
- Beans: Soak overnight to increase digestibility
- Nuts and Seeds: Soak at least 20 minutes, or better, overnight. to decrease the amount of anti-nutrients and increase digestibility.
- Soy: Opt for non-GMO and consider tempeh in place of tofu, as it is fermented and thus also provides good bacteria for the gut.
Bioavailability of Plant-based Protein
One thing to note when it comes to plant-based protein sources is that plant-based protein is less digestible (60-80%) than animal sources (>90%).
This means in addition to mixing various sources, a higher total amount needs to be consumed to achieve the target of amino acids.
This is where plant-based protein powders can help to increase protein intake. Moreover, the processing of vegan protein powders also helps in decreasing the “anti-nutrients” found in foods which hinder the nutrient absorption in the stomach. These anti-nutrients can also be decreased in the food by following practices such as soaking, fermenting or sprouting. For example, soaking lentils 2-4 hours or beans around 8-12 hours.
How much protein do you need?
The Recommended Dietary Allowance (RDA) for protein is 0.8g/kg of body weight (0.36g/lb). That is the minimum amount needed to keep one from getting sick.
However, numerous studies indicate that protein requirements for active individuals are higher than that.
The International Society of Sports Nutrition suggests that active individuals ingest protein ranging from 1.4-2.0 gm/kg per day Individuals engaging in endurance exercises should consume around 1.4g/kg of protein per day. Those engaging in activities such as football should consume around 1.7g/kg per day. And those involved in heavy weight training should consume 2g/kg per day.
Before shoving down a bunch of protein down the throat, let us understand one concept, “Nitrogen Balance”.
When we consume protein from food or supplements, nitrogen enters our body and it exits in urine as ammonia, urea and uric acid (breakdown products of protein).
When the amount of protein we eat matches the amount we use, we are in nitrogen balance.
Meaning, if we do not eat enough protein, we would be in a negative nitrogen balance and will not be able to repair muscle after a workout. And, if we consume too much protein, we would be in a positive nitrogen balance to repair muscle. however too much of a positive nitrogen balance has side effects.
Firstly, once we reach about 250 grams of protein, our body can no longer convert ammonia to urea and ammonia, which is considered a toxic compound for the body begins to build up. This causes extreme stress to internal organs, especially kidneys. Secondly, excess protein can cause dehydration if our water intake is not enough, as kidneys need more water to convert ammonia to urea. And finally, excess protein intake and constantly positive nitrogen balance is correlated to increased activity in mTOR (mammalian target of rapamycin) gene in the body which is correlated to accelerated aging.
So how much do you need?
Some studies show that even for highly active individuals, there is not much additional benefit of exceeding 1.2g/kg protein per day if you want to maintain nitrogen balance. If you want to exceed that, let’s say to put on muscle, then you do not need to exceed 1.5g/kg per day.
Sample High-Protein Meals/Snacks
- Oatmeal with nuts and seeds
- Salad with chickpeas or black beans
- Lentil soup
- Bean Chilli
- Plain Yoghurt with Berries
- Tofu stir fried with vegetables
- Quinoa salad
- Grilled Fish
- Grilled Chicken Breast
Protein Supplements
If you need to consume supplements to achieve your target of protein requirement, make sure you choose one made from the milk of grass-fed cows (if choosing whey) and is without any antibiotics, hormones, additives, and artificial flavours/colors. Prefer the unflavoured ones and flavour them yourself by adding cocoa powder/fruits/berries and stevia. If choosing a vegan protein powder. prefer an organic one.
When it comes to protein bars/snacks, make sure it is not filled with vegetable oil (which we learned are evil in the last article) and try no to consume them every other day as most are filled with vegetable oils, sugars or artificial sweeteners (such sucralose).
Food and Mood
What we eat, affects how we feel. But how?
Interestingly, our gut is connected to our brain via a communication network known as the “Gut-Brain Axis”. This explains feelings such as getting butterflies in the stomach before going on a stage, overeating when anxious helps produce extra feel-good chemicals, and feeling stupid or lethargic due to an unhealthy gut.
According to research, 95% of “Serotonin”, a neurotransmitter that helps regulate sleep, appetite, mood and inhibit pain is produced in the gut. The production of serotonin and other neurotransmitters is influenced by the billions of “good” bacteria that live in our intestines, particularly the large intestine. The colony of the bacteria in the gut is known as the “Gut Microbiome”.
The bacteria in the gut microbiome also helps us digest our food, regulate our immune system, limit inflammation, improve nutrient absorption and protect against bad bacteria that cause diseases in addition to influencing production of neurotransmitters and thus our mood and energy levels.
Interestingly, these microbes outnumber the human cells ten to one, meaning we are more bacteria than human (including the fungi and viruses that live on the human body).
Now, when we eat processed/packaged food such as canned food, sugary drinks, packaged snacks, pastries, chicken nuggets, or instant noodles which is filled with chemical additives, hydrogenated fats, artificial flavorings and colorings and artificial sweeteners (such as sucralose), it negatively affects the gut microbiome which can lead to diseases such as asthma, obesity, diabetes and brain and mood issues such as anxiety or depression.
So how to keep the microbes in our gut happy, so we can be happy?
Research shows that the following strategies can help improve gut microbiome:
- Eat fresh and whole foods
- Avoid packaged and processed food
- Eat fiber rich foods (such as whole grains and legumes)
- Eat probiotic rich foods such as plain yogurt
- Eat fermented foods such as kefir, sauerkraut or kimchi
- Eat a wide variety of colorful fresh fruits and vegetables
- Prefer organic foods if possible
One thing to note here is that there is no one size fits all when it comes to diet. Each person has a unique response to certain foods which in addition to the microbiome is also based on genes and environment. If you want to go a step further in your health, companies such as Viome offer a gut microbiome test that you can take from home and get a report with detailed information about your personal microbiome health and which foods you should eat and avoid.
Series Takeaway
In Part-I of the series, we learned why we eat which is to fuel the body and brain.
I will expand on it here a bit to mention a beautiful explanation I stumbled upon while researching for this article. Eva Selhub, MD mentions in the article “Nutritional psychiatry: Your brain on food” that your brain is always “on”, taking care of thoughts, movements, breathing, and much more. It requires constant fuel, and like an expensive car, “premium fuel” to function at best. When you fuel it with anything less than premium fuel, such as refined food or damaged fat, it causes problems including insulin resistance and inflammation (as we learned in Part-I and Part-II).
So what is premium fuel? Premium fuel is high-quality food that contains lots of vitamins, minerals and antioxidants, and thus protects the brain from oxidative stress (the waste or free radicals produced when the body uses oxygen).
When it comes to Carbs, prefer complex-carbohydrates and avoid refined carbs. Be careful about hidden sugar (such as in pasta sauces, granola bars, salad dressings,breakfast cereal).
When it comes to Fat, avoid vegetable oils and opt for healthy sources such as coconut oil/ghee for saturated fat, and nuts, seeds, olive oil, avocados. Increase omega-3 consumption by eating fish twice a week, eating walnuts, flax seeds, or taking supplements such as fish oil or algae oil.
When it comes to Protein, opt for organic, grass-fed meat sources and combine various plant-based organic sources (grains,beans,legumes,nuts). If using supplements, carefully scan and understand all the ingredients.
Keep your “Gut Microbiota” healthy by following the strategies mentioned in this article.
Most importantly, avoid packaged/processed food and be mindful of all the hidden ingredients (such as vegetable oil or sugar) when eating outside at restaurants.
Closing Thoughts
Hooray! You finished reading the series. Congratulations 🙂
Hopefully, this series has provided you, the reader, some knowledge that will help you make better decisions regarding your food choices. Do not forget to share it with your loved ones who could benefit from this information.
Let us know in the comment section if you have any feedback, question, or request for another series of articles.
Cheers! Take care.
References
- https://www.livescience.com/53044-protein.html#:~:text=Protein%20is%20a%20macronutrient%20that,Macronutrients%20provide%20calories%2C%20or%20energy
- https://www.innerbody.com/nutrition/macronutrients#understanding-proteins
- https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/
- https://bengreenfieldfitness.com/article/how-much-protein-do-i-need/
- https://pubmed.ncbi.nlm.nih.gov/2745350/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2129150/
- https://www.helpguide.org/articles/healthy-eating/choosing-healthy-protein.htm
- https://www.helpguide.org/articles/healthy-eating/choosing-healthy-protein.htm
- https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/
- https://www.health.harvard.edu/blog/nutritional-psychiatry-your-brain-on-food-201511168626
- https://www.health.harvard.edu/blog/gut-feelings-how-food-affects-your-mood-2018120715548