Therefore, A Correct Diet Shall Include Animal Protein of High Biological Value

This is a sentence taken from a textbook I picked up that I fell in love with after reading into it somewhere–perhaps PubMed or at the publisher’s site, where they allowed to read a small part of a chapter.

Medical Biochemistry

It is originally written in Spanish and translated to English, published in 2017. Why do I think that non-American text books are always better than American?… my be my imagination… In any case, I started reading the book and have experienced about one aha moment per 5 minutes. The title sentence to the article is most certainly a provocative last sentence of a section about proteins (page 47 for those inclined to find it). Here is the full quote:

The main function of proteins is structural, a role that cannot be replaced by any other components of the diet.

Within the existing amino acids, eight (phenylalanine, isoleucine, leucine, lysine, methionine, threonine, tryptophan, and valine) cannot be synthesized by humans. These amino acids are designated essential or indispensable and must be necessarily supplied by protein present in foods…

From a nutritional point of view, the quality or “biological value” of dietary proteins depends on their content of essential amino acids. Animal proteins (from red and white meats, milk, and eggs) are generally of higher biological value than those from plants. Therefore, a correct diet shall include animal protein of high biological value. (emphasis by me)

This captivated me since about 2 weeks ago I published an article on a blog where I am a scientist blogger about proteins and came to the same conclusion, going so far as to calculating the biological value of several foods to see what would have the highest biological value. I used the most common foods that we would pick but no doubt it could be extended to see what we really should eat, by calculating the biological value for a lot of foods.

biological value of some foods

I encircled with red the biologically essential values, which are calculated by adding up all the essential amino acids***: Histidine, Methionine, Valine, Leucine, Lycine, Isoleucine, Phenylalanine, Tryptophan, and Threonine  and dividing its sum by the sum of all of the nonessential amino acids in the food: Alaline, Arginine, Asparagine, Aspartate, Cysteine, Glutamate, Glutamine, Glycine, Proline, Serine, and Tyrosine. ***Note that some essential amino acids can be synthesized by the human body so this list contains all essentials whereas the quote above contains only 8, which we cannot synthesize.*** You can find the amino acid content of most foods in the USDA database when you click on “full report (all nutrients)” after your food selection. Here is an example for porterhouse steak, scroll to the bottom where the amino acids are listed and write them out one by one–yes, it is painfully tedious.

However, the outcome of this research is very important: it allows you to see what foods to eat and what not to eat.

Chemical Composition of Human Tissues

This is an important section–here I provide a cell phone photo of a paperback, so not very good quality, but you can see some important points.

body macronutrient ratios

The importance of this table is that while we are told left and right to stuff our faces with carbohydrates, our body doesn’t contain carbs much–only a bit of glucose in our muscles and blood and a bit of glycogen in the liver. Yet food elements we are told to not eat, such as fat and cholesterol, occupy a huge portion of our brain, and good portion of the liver and muscles. Proteins occupy the most of everything other than water and before you yell that bone marrow is lipids: nope. Bone marrow is where we make our red blood cells. It is not lipids.

So then, since proteins make up the biggest part in our body (more than calcium in our bones) other than water, we really should be spending much time figuring out what proteins we are going to eat. As I have shown in the table above, the quote is correct: we need to focus on animal products and not vegetables.

Elements of the Human Body and Their Relative Abundance

And finally, now about the general mineral levels in our body. This is an important table because we have no idea how much sodium, for example, our body contains all the time. So when the USDA recommends to reduce our daily salt consumption, what will that do to our body? Do we store salt anywhere and how much? How important is salt anyway? I think this table provides a pretty good demonstration of how important these minerals are–and if they are that important.

body mineral levels

Thus you can calculate that since sodium represents 0.20% of our weight, an average 150 lbs person contains ~0.3 lbs or 5.33 oz sodium. Sodium is 40% of salt, therefore the total salt is 13.325 oz, or about 0.83 lbs salt. That is close to 1 pound salt in the body of a 150 lbs person. That’s a LOT of salt. So two points can be made here:

1. Reducing or increasing our salt a bit a day should not make much of a difference, provided we don’t let our salt storage run out
2. Salt must be extremely important for us if we carry almost a pound of it around in our body, 1/5th the amount of calcium, something our bones are made of!

At the same time, should you ever supplement with Zink or Selenium? Nah.. they are trace. This book is really helping me see the human body in a very interesting way. I can certainly see that the individual parts of our body are much more important than the sum.

My Most Controversial Conclusion Ever

The vegan and the vegetarian diets are not sufficient for a human to remain healthy.

We can argue about ethics, climate change, gas emission by the cows, the hormones and antibiotics that are given to them to sustain some semblance of their lives, given how they are fed the wrong food and are cramped up into tiny quarters. All that is happening to them in order to allow for huge fields for the wasted food stuff growing, such as corn and soy, whose nutrition is not biologically valuable enough to sustain our lives.

Comments are welcome, as always, and are monitored for appropriateness.

Angela