Of the common sources of plant protein that Australians eat – grains, legumes, nuts and soy – nuts generally have the highest plant protein content per 100g (1).

For instance, almonds and pistachios have 20g plant protein per 100g, compared to soybeans at around 14g, tofu at 12g, chickpeas at 6g, and oats with 2-3g. Some seeds are also particularly rich in plant-based protein.

Most tree nuts provide 3-6g protein per 30g handful – or around 10-20g of protein per 100g.

Table: Protein content of some plant-protein food sources (1)

Food Serve size*Protein (g) per serveProtein (g) per 100g
Pumpkin seeds30g9.030.2
Sunflower seeds30g8.026.8
Almonds30g5.919.7
Pistachios30g5.919.7
Cashews30g5.117.0
Chia seeds30g5.016.5
Hazelnuts30g4.514.8
Brazil nuts30g4.514.4
Walnuts30g4.314.4
Kidney beans (canned)75-150g10.5-21.014.0
Soybeans (dried, boiled)75-150g10.1-20.313.5
Pine nuts30g3.913.0
Tofu170g20.412.0
Wholewheat breakfast biscuits30g (2 biscuits)3.612.0
Wholemeal bread40g (1 slice)4.511.2
Pecans30g2.99.8
Macadamias30g2.89.2
Lentils (dried, boiled)75-150g5.6-11.17.3
Chickpeas (canned)75-150g4.7-9.36.3
Baked beans (canned)75-150g3.7-7.44.9
Chestnuts30g1.03.4
Rice (white, boiled)1/2 cup (80g)2.22.7
Potato75g (1/2 medium)1.92.5
Oats (cooked porridge)1/2 cup (120g)2.92.4
Apple150g (1 medium)0.50.3

*Based on the serve sizes outlined in the Australian Guide to Healthy Eating. Note: A serve of legumes is: as a vegetable serve = 75g (½ cup cooked legumes); as a meat alternative serve = 150g (1 cup cooked legumes)

What about protein quality?

The protein digestibility (or ‘protein quality’) of tree nuts is similar to many other plant protein sources (2-4). Soy is the only plant protein source that scores 100 per cent (the same as animal protein).

Table: Protein Digestibility Corrected Amino Acid Score (PDCAAS) of some tree nuts

Cashews90%
Almonds*73%
Pistachios73%
Walnuts66%
Brazil nuts63%

*Tropical almonds

Combining different sources of plant protein across the day increases the protein quality. For example, eating both nuts and legumes over the day provides us with all nine essential amino acids, lifting protein digestibility to 100 per cent!

The take-home here is that people who eat vegetarian or vegan diets need a variety of protein sources, from a range of plant-based foods, throughout the day to get their essential amino acids.

Nuts for plant-based nutrition . . . beyond protein!

Nuts offer equivalent or higher levels of a wide range of nutrients and bioactives, including healthy unsaturated fats, phosphorous, copper, manganese and melatonin, compared with other sources of plant protein.

References

  1. AUSNUT 2011-2013 AHS. Food Nutrient Database.
  2. Loveday SM. Food proteins: Technological, nutritional, and sustainability attributes of traditional and emerging proteins. Annu Rev Food Sci Technol, 2019. 10:311-39.
  3. Boye J., et al. Protein quality evaluation twenty years after the introduction of the protein digestibility corrected amino acid score method. Br J Nutr, 2012. 108(S2):S183-S211.
  4. Freitas JB., et al. Edible seeds and nuts grown in Brazil as sources of protein for human nutrition. Food Nutrition Sciences, 2012. 3(6):857-62.
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