Plant & Animal Proteins - the Building Blocks of the Body
Channel: Maya Adam
Date: 2016-01-15

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Transcript:

Protein-rich foods, including animal and plant-based proteins, can also vary enormously in their quality and their implications for our long-term health.

Proteins are often said to act as building blocks for the lean tissues in our bodies, but they serve many other important functions in body regulation, support of immune function and a variety of other roles in our physiology. 

There are 20 types of amino acids needed to fulfill all of these functions, but only 9 of them are essential, meaning that our bodies can’t make enough of them – so we rely on getting these from our food. In general, animal sources of protein, like fish and eggs, provide all of the essential amino acids in high enough concentrations that these foods are called complete protein sources. In contrast, plant-based protein sources, like beans, lentils, nuts and tofu, tend to be incomplete sources of protein.

It might seem that, since plant-based proteins are incomplete in their nutrient content, that they’re nutritionally inferior compared with animal based proteins, but in fact, the health benefits of substituting plant-based proteins for animal-based ones, ideally a few days a week, far outweigh the risk of falling short on essential amino acids.
This is because plant-based proteins can be combined with other foods to provide a complete amino acid profile. In fact, many traditional food combinations, like rice and lentils or corn and black beans, are based on the principle of combining complementary proteins. These meals also contain valuable fiber and they’re likely to be lower in fat, especially saturated fat, than a meal that features animal protein.

Michael Pollan: what we do know, with a great deal of confidence, is that populations who eat this diet, and it's normally defined as a diet high in meat, high in processed foods with very little whole grains, very little fruits and vegetables, that people who eat that way, populations who eat that way, have very high rates of chronic disease.

So, when people are on low-carb, high protein diets, it’s important to ask what kinds of proteins are being consumed and in what quantities. A diet high in animal protein, especially if it’s poor-quality animal protein like processed meat or high fat cuts of meat, can be harmful to our health. Processed meats often contain nitrates, used as a preservative, which can damage blood vessels and contribute to atherosclerosis. These meats also tend to be very high in sodium which can be a contributor to hypertension.

The simplest advice is to choose moderate amounts of high-quality protein-rich foods from a variety of different sources, including some fish if possible as well as vegetarian sources of protein that are combined for completeness. Oversimplified, nutrient-focused dietary advice, like diets that encourage patients to eliminate all carbohydrates, including whole grains, while they consume as much protein as they want regardless of the quality, these diets almost never lead to sustainable, long-term health.

The human body is a complex organism that depends on interrelated systems working together within tightly regulated parameters. One of the best ways to protect a system like this is to provide it with the dietary complexity we get from a well-balanced meal – that includes a variety of whole foods.

Course by Maya Adam, MD
Directed by William Bottini
Editing by William Bottini & Tamsin Orion
Special thanks to Michael Pollan, Tracy Rydel, and David Eisenberg