Plant-based diets are becoming more popular in many countries, due to their many benefits for health and the environment. However, shifting to a plant-based diet can raise concerns about achieving nutritional balance, particularly when it comes to protein intake and protein quality. Dr. Christopher Marinangeli of Protein Industries Canada and his colleagues recently explored plant protein consumption and its effects on protein quality and nutrient intake. Read More
Using data from the US National Health and Nutrition Examination Survey, Marinangeli and colleagues analyzed the diets of nearly 15,000 adults. They found that as the intake of plant protein increases, the total amount of protein consumed decreases. This is because plant proteins tend to be less concentrated sources of protein compared to animal-based options. Additionally, the digestibility and amino acid profiles of plant proteins can vary, making some less effective at supporting the body’s needs unless they are carefully combined.
The team’s research found that cereal grains are the predominant source of plant protein. While grains can be convenient sources of protein, they are not considered a “protein food.” They can also be relatively low in protein and certain essential amino acids, especially lysine. Legumes, which are richer in protein and essential amino acids, are not widely consumed, even though the team’s study showed they are the most cost-effective plant protein source.
Marinangeli and colleagues also found that diets higher in plant protein tend to be richer in fiber, and key nutrients including folate, zinc and iron. However, these diets are lower in vitamins B12 and D, which are primarily found in animal products. This highlights the need for careful dietary planning when plant protein represents the majority of protein in a person’s diet, and animal protein intake is limited. Some of these strategies can include looking for fortified foods or using supplements.
To address concerns about protein quality, the study explored how blending different plant proteins could improve the balance of amino acids.
Marinangeli and colleagues modeled a dietary shift, where 50% of the amino acids from grains were replaced with those from legumes. This simple adjustment improved the overall protein quality of the diet by 10%, demonstrating that strategic food combinations can help people meet their nutritional needs while consuming more plant proteins.
The study emphasizes that while increasing plant protein intake can be beneficial, it requires mindful food choices to maintain adequate protein intake, protein quality and overall nutrient intake. The team’s findings offer practical insights for people who want to adopt a more plant-based diet, while ensuring they get the essential nutrients they need.
