Protein

Protein is a macronutrient made up of amino acids, which the body uses to build and repair tissues, make enzymes and hormones, and support immune function. A common question about veganism is whether a diet without animal products provides enough protein. Major dietetic organisations, including the Academy of Nutrition and Dietetics, state that a varied vegan diet that meets energy needs can provide adequate protein.

How much protein is needed

The US Recommended Dietary Allowance (RDA) for adults is 0.8 g of protein per kilogram of body weight per day. EFSA's population reference intake for adults is similar, at 0.83 g/kg. For a 70 kg adult this is roughly 56–58 g per day.

Needs are higher in some groups:

• pregnancy and breastfeeding (see vegan pregnancy and children);
• older adults, for whom some experts suggest intakes above the RDA to help preserve muscle;
• athletes and people doing heavy training (see vegan athletes).

Some dietitians suggest that vegans aim slightly above the RDA to allow for the somewhat lower digestibility of certain plant proteins, particularly in diets high in whole grains and fibre.

Amino acids and lysine

Of the twenty amino acids used to build proteins, nine are essential: they must come from food. All plant foods contain all nine essential amino acids, but in different proportions.

Lysine is the essential amino acid most likely to be low in vegan diets, because cereal grains such as wheat, rice and maize contain relatively little of it. Legumes (beans, lentils, peas, chickpeas, peanuts and soya) are rich in lysine. Diets that include legumes daily therefore tend to meet lysine needs comfortably. Other good sources include tofu, tempeh, quinoa, pistachios and pumpkin seeds.

Protein combining

The older idea that plant proteins must be carefully "combined" at every meal (for example, beans with rice) is no longer considered necessary. The Academy of Nutrition and Dietetics notes that eating a variety of plant foods over the course of a day supplies all essential amino acids. Combining foods remains a sensible habit, but strict meal-by-meal matching is not required.

Sources

The table below shows approximate protein content of common vegan foods. Values vary by brand, variety, recipe and preparation, so they should be treated as rough guides only. Legumes and grains are given as cooked weight.

Many processed meat alternatives and protein-enriched products also contribute substantial protein; their nutrition labels give exact values. See seitan, tofu and tempeh for more on these foods.

Practical tips

• Include a legume or soya food at most meals, such as lentil soup, hummus, tofu scramble or bean chilli.
• Choose wholegrain breads, pasta and rice, which contribute more protein than refined versions.
• Use nuts, seeds and nut butters as snacks and toppings.
• Choose soya milk or pea-protein milk when protein content matters, as many other plant based milks such as almond, oat and rice are low in protein.
• Ensure overall energy intake is sufficient; if calories are too low, protein is used for energy rather than tissue building.

Protein quality

Protein quality is often assessed using scores such as PDCAAS or DIAAS, which consider amino acid profile and digestibility. Soya protein scores highly on these measures, while many grains score lower, mainly because of lysine. Mixing several protein sources raises the quality of the overall diet. Processing methods such as cooking, soaking, sprouting and fermenting can also improve digestibility.

This article provides general information. Individuals with specific health needs should consult a doctor or registered dietitian for personal advice.

See also

• meal planning
• iron
• zinc
• vegan on a budget