Vegan Diets: Protein Deficiency Or Not?

Protein is an essential nutrient involved in virtually all cell functions. In the body, protein is required for structural support, and the maintenance and repair of tissues. It is also the basic component for immunity, most hormones, and all enzymes, among other functions.

A common concern about vegetarian and vegan diets is that they may lack sufficient protein. However, vegans can get protein from various plant sources, though some may be better than others.

Protein-rich plant foods include seitan, tofu, beans, lentils, nuts, seeds, and grains.

Research suggests that higher protein diets can promote muscle strength, feelings of fullness, and weight loss.

In addition, while well-planned vegan diets made up of mostly minimally processed foods are considered beneficial for all stages of life, those including large amounts of ultra-processed plant foods are not.

The body's protein requirements

Protein is an essential macronutrient that accounts for about 17% of the body's weight. It is the main component of muscles, skin, internal organs, hair, nails, antibodies, enzymes, and more. The body uses protein to build, maintain, and repair itself.

The amount of protein an individual needs depends on their age, sex, weight, height, and physical activity level, among other factors. The Recommended Dietary Allowance (RDA) for protein is 0.8 grams of protein per kilogram of body weight, or 0.36 grams per pound, which is the minimum amount needed to keep from getting sick.

The amount of protein a person needs can vary depending on their calorie intake, age, sex, and physical activity level.

• For a sedentary 50-year-old woman weighing 140 pounds, this translates to 53 grams of protein per day.
• During pregnancy, protein requirements increase to 75-100 grams per day for the developing foetus and the mother's body.
• Physically active individuals, including athletes, may require higher amounts of protein, ranging from 1.3-2 grams of protein per kilogram of body weight.

Meeting Protein Requirements on a Vegan Diet

It is possible for vegans to meet their protein requirements by consuming a variety of plant-based protein sources, including:

• Hemp seeds: 30 grams of protein per 100 grams.
• Peanuts: 25.8 grams of protein per 100 grams.
• Pumpkin seeds: 24.4 grams of protein per 100 grams.
• Tempeh: 20.7 grams of protein per 100 grams.
• Cashew nuts: 17.7 grams of protein per 100 grams.
• Soya mince: 16.6 grams of protein per 100 grams.
• Tofu: 16.5 grams of protein per 100 grams.
• Chia seeds: 16.5 grams of protein per 100 grams.
• Lentils: 8.8 grams of protein per 100 grams.
• Chickpeas: 7.2 grams of protein per 100 grams.
• Baked beans: 5 grams of protein per 100 grams.
• Quinoa: 4.4 grams of protein per 100 grams.
• Brown rice: 3.6 grams of protein per 100 grams.
• Buckwheat: 3.4 grams of protein per 100 grams.
• Oats: 2 grams of protein per 100 grams.

By including a variety of these protein sources in their diet, vegans can ensure they are meeting their body's protein requirements.

The myth of protein combining

However, this is a myth that has been debunked by the scientific nutrition community. While it is true that some plant-based foods are missing an amino acid here and there, it is not true that vegans and vegetarians need to carefully combine plant-based proteins to avoid deficiency. As long as a variety of plant-based protein sources are eaten, the body can store and mix and match amino acids to whatever proportions are needed.

In 1981, Lappé herself changed her position on protein combining, writing:

> "In 1971 I stressed protein complementarity because I assumed that the only way to get enough protein ... was to create a protein as usable by the body as animal protein. In combating the myth that meat is the only way to get high-quality protein, I reinforced another myth. I gave the impression that in order to get enough protein without meat, considerable care was needed in choosing foods. Actually, it is much easier than I thought."

In 1988, the American Dietetic Association also reversed its position, with primary author Suzanne Havala stating:

> "There was no basis for [protein combining] that I could see.... I began calling around and talking to people and asking them what the justification was for saying that you had to complement proteins, and there was none. And what I got instead was some interesting insight from people who were knowledgeable and actually felt that there was probably no need to complement proteins."

In 1994, Vernon Young and Peter Pellett published a paper that became the definitive contemporary guide to protein metabolism in humans, confirming that combining proteins at meals was unnecessary. The American Dietetic Association, the American Heart Association, and the Academy of Nutrition and Dietetics have all since stated that people who avoid consuming animal protein do not need to be concerned about amino acid imbalances.

Recommended dietary intakes

Protein is an essential part of our nutrition, making up about 17% of the body's weight. It is the main component of our muscles, skin, internal organs, eyes, hair, and nails. Our immune system requires protein to make antibodies to fight infections, and protein also plays a role in blood sugar regulation, fat metabolism, and energy function.

Protein is made up of long chains of smaller units called amino acids. There are 20 amino acids in total, nine of which are essential, meaning that the body cannot make them, and they must be obtained from your diet. Animal foods like meat and fish are often referred to as 'complete' sources of protein, meaning they contain all nine essential amino acids. However, certain plant sources are also complete, while others may be lacking in sufficient amounts of some essential amino acids.

The Reference Nutrient Intake (RNI) for an average adult is set at 0.75g of protein per kg of body weight per day. This means an adult weighing 60kg needs 45g of protein per day, while an adult weighing 74kg would need 55g. The RNI is a minimum amount and is based on the needs of an average, sedentary adult. As a vegan, it is recommended to have three plant-based protein sources per day, spread evenly throughout the day to optimise your body's use of protein.

There is some evidence to suggest that eating too much protein may be bad for you, but this typically relates to diets high in animal proteins such as dairy and red or processed meats. A prolonged intake of high amounts of protein was once thought to contribute to bone loss and kidney damage. However, studies now suggest that, in otherwise healthy individuals, there is little evidence of this effect.

A high-protein diet does appear to be a problem for those with an existing condition or kidney dysfunction, but in healthy people, including the elderly, higher protein intake may be beneficial as it may help prevent muscle loss. Little research has been conducted into the risks associated with high-protein vegan diets, although it is always important to ensure that there is variety and attention is paid to vitamin and mineral requirements, especially during pregnancy.

Plant foods can be a great source of protein and are beneficial if you are eliminating or reducing the amount of dairy, eggs, and meat in your diet. Here are some examples of plant-based protein sources:

• Hemp seeds: 30g of protein per 100g
• Peanuts: 25.8g of protein per 100g
• Pumpkin seeds: 24.4g of protein per 100g
• Tempeh: 20.7g of protein per 100g
• Cashew nuts: 17.7g of protein per 100g
• Soya mince: 16.6g of protein per 100g
• Tofu: 16.5g of protein per 100g
• Chia seeds: 16.5g of protein per 100g
• Lentils: 8.8g of protein per 100g
• Chickpeas: 7.2g of protein per 100g
• Baked beans: 5g of protein per 100g
• Quinoa: 4.4g of protein per 100g
• Brown rice: 3.6g of protein per 100g
• Buckwheat: 3.4g of protein per 100g
• Oats: 2g of protein per 100g

Vitamin B12

The body needs vitamin B12 to maintain healthy blood and a healthy nervous system. Many people get vitamin B12 from animal sources, such as meat, fish, and dairy products. Sources for vegans are limited, and a vitamin B12 supplement may be needed.

The recommended daily intake of vitamin B12 is 2.4mcg for adults, 2.6mcg during pregnancy, and 2.8mcg while nursing.

Calcium

Calcium is needed to maintain healthy bones and teeth. Non-vegans get most of their calcium from dairy foods, but vegans can get it from other foods.

Good sources of calcium for vegans include:

• Green, leafy vegetables such as broccoli, cabbage, and okra
• Fortified unsweetened soya, pea, and oat drinks
• Sesame seeds and tahini
• Brown and white bread
• Dried fruit, such as raisins, prunes, figs, and dried apricots

Iron

Iron is essential for the production of red blood cells. A vegan diet can be high in iron, although iron from plant-based food is absorbed by the body less well than iron from meat.

Good sources of iron for vegans include:

• Wholemeal bread and flour
• Breakfast cereals fortified with iron
• Dark, green, leafy vegetables, such as watercress, broccoli, and spring greens
• Dried fruits, such as apricots, prunes, and figs

Vitamin D

The body needs vitamin D to regulate the amount of calcium and phosphate in the body. These nutrients help keep bones, teeth, and muscles healthy.

Good sources of vitamin D for vegans include:

• Exposure to sunlight, particularly from late March/early April to the end of September
• Fortified fat spreads, breakfast cereals, and unsweetened soya drinks
• Vitamin D supplements—everyone should consider taking a daily supplement during autumn and winter, as it is difficult to get enough from food alone

Omega-3 fatty acids

Omega-3 fatty acids, primarily those found in oily fish, can help maintain a healthy heart and reduce the risk of heart disease when eaten as part of a healthy diet.

Sources of omega-3 fatty acids suitable for vegans include:

• Ground linseed (flaxseed) oil
• Vegetable (rapeseed) oil

Do vegetarians get enough protein?

Vegetarians can get enough protein from plant sources, but it's important to eat a variety of foods to ensure adequate intake. While animal products are rich in protein, the adequacy of protein intake from vegetarian/vegan diets has long been a topic of debate in the field of nutrition.

Protein requirements

The Recommended Dietary Allowance (RDA) for protein for adults is 0.8 grams per kilogram of weight. To calculate your individual daily protein needs, multiply your weight in pounds by 0.36 to get your recommended protein intake in grams. For example, a 170-pound male requires about 60 grams of protein per day, while a 130-pound female requires about 47 grams.

The Reference Nutrient Intake (RNI) for an average adult is set at 0.75 grams of protein per kilogram of body weight per day. This means that a person weighing 60 kg needs 45 grams of protein per day, while a 74 kg person would need 55 grams. The RNI is a minimum amount based on the needs of a sedentary adult. As a vegan, aim to include three plant-based protein sources in your daily diet, spread evenly throughout the day to optimise your body's use of protein.

Sources of protein for vegetarians

Vegetarians can obtain protein from a variety of plant sources, including legumes, soy products, grains, nuts, and seeds. Examples of protein-rich plant foods include:

• Seitan
• Tofu, tempeh, and edamame
• Lentils
• Beans, including kidney, black, pinto, and chickpeas
• Nutritional yeast
• Hemp seeds
• Green peas
• Spirulina
• Amaranth and quinoa
• Ezekiel bread and other sprouted grains
• Soy milk
• Oats and oatmeal
• Chia seeds
• Nuts, nut butter, and other seeds
• Fruits and vegetables like broccoli, spinach, asparagus, artichokes, potatoes, sweet potatoes, and Brussels sprouts
• Mycoprotein

Benefits of plant-based proteins

Plant-based proteins are generally considered healthier because they are accompanied by fibre and cancer-fighting phytochemicals. They also tend to be low in fat and cholesterol-free. Additionally, plant proteins are often lower in saturated fat and free of cholesterol and haem iron, which may contribute to a reduced risk of chronic diseases such as diabetes and heart disease.

Concerns about protein deficiency

Protein deficiencies among vegetarians and vegans are uncommon, especially for those following a healthy, well-planned diet. However, some people may need to increase their plant protein intake for various reasons. It's important to note that poorly planned or highly processed vegan diets may increase the risk of nutrient deficiencies, especially in vitamin B12, iodine, iron, calcium, zinc, and long-chain omega-3s.

The benefits of plant protein

Protein is an essential macronutrient that supports energy levels, builds muscle mass, and is important for the formation of enzymes and neurotransmitters. While animal products are a rich source of protein, plant proteins have several advantages. Here are some benefits of incorporating plant protein into your diet:

• Cardiovascular Health: Plant proteins are typically lower in saturated fat, which contributes to lower cholesterol levels. Plant sterols found in plants are also beneficial for heart health.
• Fewer Added Hormones and Antibiotics: Plant-based proteins are free of added hormones and antibiotics, which are commonly used in industrial animal farming.
• Positive Environmental Impact: Producing plant-based proteins has a lower environmental impact than animal-based proteins, requiring less water, emitting fewer greenhouse gases, and utilising less land.
• Rich in Minerals and Vitamins: Plants provide the body with essential nutrients, including vitamins, minerals, phytochemicals, and antioxidants.
• High-Protein Options: Legumes (beans, edamame, peas, chickpeas, lentils, soy), whole grains (amaranth, buckwheat, spelt, millet, oats, quinoa, rice), nuts and seeds (chia seeds, peanuts, hemp seeds, pumpkin seeds, almonds, pistachios, sesame seeds, sunflower seeds) are all excellent sources of plant-based protein.

In addition to these benefits, plant proteins offer a slower digestion rate due to their fibre content, keeping you fuller for longer. They also provide all the essential amino acids your body needs when consumed in a well-balanced diet.

While vitamin B12 may be a concern for those on a strictly vegan diet, this can be easily supplemented or obtained from nutritional yeast.

Plant proteins are a healthy and nutritious option, offering a wide range of benefits that support overall health and well-being.

Frequently asked questions