• Connor McDermott

Different Types of Protein: What Should I Eat?

Protein is a vital nutrient required for building, maintaining, and repairing tissues, cells, and organs throughout the body as well as fighting viral and bacterial infections. Luckily for us, there are numerous sources of protein to choose from, including whole foods and protein supplements.

Smoothies, with their excellent versatility, provide the perfect opportunity to increase your protein intake. Adding protein to a smoothie is not just a good idea – it is a great idea. There are many different options for adding protein to your smoothie, so many in fact that it can be overwhelming at times. Learning about different sources of protein is the best way to decide which ones are the best fit for your diet and your needs. First, let us start with understanding the two basic types of proteins in foods – complete and incomplete proteins.

Complete vs. Incomplete Proteins

The quality of a protein is crucial when considering the nutritional benefits that it can provide. Determining the quality of a protein is determined by assessing its essential amino acid composition, digestibility, and bioavailability of amino acids.

Typically, all dietary animal protein sources (beef, eggs, poultry, seafood, dairy) are considered to be ‘high quality’ complete proteins. Most plant protein sources in contrast are ‘lower quality’ incomplete proteins, comprising most starches (such as grains, potatoes, legumes) and all vegetables. Though some plant proteins (such as those found in buckwheat, quinoa, and soy) are complete proteins, the majority of plants contain just some of the essential amino acids. Someone who desires to get their protein from vegetable sources will need to consume a variety of vegetables, fruits, grains, and legumes to ensure consumption of all essential amino acids. This can be accomplished through protein complementation. Protein complementation is when you combine two vegetable proteins (legumes and grains for an example) to get all 9 amino acids that are essential for your body. If a diet relies on incomplete plant-based proteins, it is important to consume a variety of protein sources to obtain all the essential amino acids.

Whole Food vs. Supplements

While most experts agree that the majority of our sources of protein should come from a mix of whole foods, this can be a challenge for some. For athletes, who generally have higher protein intake needs, supplementation with protein powders is an easy, convenient, and often quicker-to-digest alternative to solid sources of protein from whole foods. Additionally, for those who follow vegetarian or vegan diets, supplements can help increase their intake of high-quality complete proteins.

However, there are things to pay attention to when using protein supplements. Protein powders may include other ingredients such as added sugars, artificial flavoring, thickeners, vitamins, and minerals. There can also be dangers with consuming certain protein powder supplements.

Anyone considering protein powder should understand that it is classified as a dietary supplement, which means it is not regulated in the same way as food or medicine. Responsibility falls on manufacturers to ensure that their products are not hazardous, though many companies do not test for safety or efficacy before their products hit shelves. Even though the FDA created Good Manufacturing Practices (GMPs) to help minimize adverse issues, compliance with these procedures remains a concern. That said, there are accredited organizations, like NSF International, that independently test supplements, including protein powders. NSF’s “Certified for Sport” designation ensures that contents match what is on the label, and that the product is GMP-registered and does not contain unsafe levels of toxic metals like arsenic and mercury.

Protein Add-Ins for Smoothies

Smoothies, especially the ones made from whole fruits and vegetables, are wonderfully healthy and nutritious. When choosing protein sources for your smoothies, look to add ingredients that are complete proteins or use “protein complementation” to form a complete protein from two incomplete proteins.

Below are lists of both common complete protein add-ins as well as common protein add-ins for complementation:

Complete Proteins Add-ins:

  • Hemp seeds

  • Chia seeds

  • Spirulina

  • Tofu

  • Cottage cheese

  • Kefir

  • Milk

  • Yogurt / Greek yogurt

  • Soy milk

  • Pea milk

Protein Complementation and Examples:

  • Beans and grains, nuts, seeds – chickpeas and sesame seeds

  • Grains and legumes – oats and peanut butter

  • Nuts/seeds and legumes – walnuts and peas

  • Vegetables and grains, nuts, seeds – spinach and sunflower seeds

This concludes the first blog of the two-part series on protein sources. The next blog posted will include information on supplemental protein in the form of protein powder. Detailed information will be provided on different types of protein powders and the pros and cons of each.


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5. PubMed Central Full Text PDF. Accessed May 26, 2020. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905294/pdf/jssm-03-118.pdf

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