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Activated nuts have become quite popular in the world of health trends these last few years. Due to claims that activating nuts improves digestion and the bioavailability (body's ability to use) nutrients, many have come to believe that they need to pay more for activated nuts, or spend time activating them, to receive true nutritional benefit.
What are 'activated' nuts?
The process of activating nuts involves soaking nuts in water for 12-24 hours before drying them at very low temperatures (this does make them super crunchy!). Nuts are the seed of a plant, and so, when soaked in water the germination process is started.
When this happens, stored nutrients like proteins and fats are broken down to be available for the seed to use as energy and begin to grow sprouts. An enzyme called phytase is also released, which breaks down phytates to make minerals available in this process. Often, salted water is used in the theory that this helps further the enzyme activity.
Okay, but what are "phytates"?
Phytates are plant compounds that bind to minerals like calcium, iron and zinc. When bound to these nutrients, it can make them a little trickier for us to access. So, in theory, you can see why some may assume this process makes the minerals in nuts more available to us.
However, despite their "anti-nutrient" properties, phytates haven't been found to be all bad. Phytates have also been found to have antioxidant, anti-inflammatory effects, also associated with improved bone mineralisation and anti-cancer properties. So, like all things in nutrition, it isn't always black and white.
Demonising or having tunnel-vision on one food or nutrient can prevent us from seeing the full picture.
So, what's the deal with phytates in grains and legumes?
The soaking of grains and legumes has been used traditionally to increase palatability, reduce cooking time and to reduce phytate content, with the hopes of improving nutrient bioavailability.
There is evidence to suggest that this does reduce the amount of phytates, making minerals easier to absorb. These findings are still inconsistent, however- not all find phytate reductions, some find increased mineral content, others find losses. Nevertheless, it is being investigated and has some supporting evidence to the theory. The true benefit in our households compared to developing countries should also be considered.
Unlike grains and legumes, it has been unknown whether the same effects, if any, are found when soaking nuts as we cannot apply this evidence to other foods.
Okay, so back to the nuts.
A recent study looked at the activation of nuts and this effect on phytates and mineral content- this was the first study to do so. That is important, as these claims have been made without any evidence supporting them prior.
The study tested different activation methods on on walnuts, peanuts, almonds and hazelnuts. It was found that activating nuts either had no significant impact on phytates, or increased the concentration. Additionally, it was found that this process resulted in up to 25% of the minerals calcium, iron and zinc to be lost. This was higher in the chopped nuts. Another concern was raised here too: using salt in this process makes these activated nuts a higher sodium option.
Overall, the process of activating nuts was not found to make minerals more bioavailable, and actually reduced the mineral content in nuts.
A previous study looked at the process of activation on phytate content and digestibility in almonds and found an increase in phytates, but also no improvement in gastrointestinal symptoms. The increase in phytates is likely due to activation not significantly altering the phytate content, but the drying process resulting in moisture loss- so, the concentration of phytates increases. The more recent study did adjust for moisture loss.
What does this all mean?
Eat nuts however you wish, but they're worth eating. A serving of raw or roasted nuts a day has been well-studied to reduce risk of heart disease, type 2 diabetes, some cancers and improved weight management.
So, don't feel you need to spend more money or time on activated nuts. I know I'll still soak nuts for some recipes I make and buy certain mixes I like, however I'm now more aware of the nutrient losses this can cause. In a similar way, if you really enjoy activated nuts or feel way better consuming nuts this way, go for it. You may just get less out of them nutritionally.
The key point is to be weary of claims made without evidence, particularly if this can result in you going without nutritious foods, or cause financial stress.
Go nuts!
Still curious? Here are some references:
Two key studies mentioned
Kumari S., et al. Does ‘activating’ nuts affect nutrient bioavailability? Food Chemistry 2020 doi: 10.1016/j.foodchem.2020.126529
Taylor H., et al. The effects of 'activating' almonds on consumer acceptance and gastrointestinal tolerance. Eur J Nutr, 2018. 57(8): p.
2771-2783.
Germination Process
Bahari, S (2012). Lipolytic activity and chilling requirement for germination of some almond cultivars African Journal of Biotechnology, 11(76): 14096-14101.
Khandelwai S, Udipi SA, Ghugre P (2010). Polyphenols and tannins in Indian pulses: Effect of soaking, germination and pressure cooking Food Research International, 43(2): 526-530.
Malhotra, RC (1931). Physio-chemical study of some economic seeds during germination with particular reference to weight and energy loss. Protoplasma 12(1):167-189.
Hahm T-S, Park S-J, Lo YM (2009). Effects of germination on chemical composition and functional properties of sesame (Sesamum indicum L.) seeds. Bioresource Technology 100(4):1643-1647.
Mubarak AE (2005). Nutritional composition and antinutritional factors of (Phaseolus aureus) as affected by some home traditional processes. Food Chemistry, 89(4):489-495.
Soaking of Grains and Legumes
Azeke AA, Egielewa SJ, Eigebogbo MU, Godwin I (2011). Effect of germination on the phytase activity, phytate and total phosphorus contents of rice (Oryza sativa), maize (Zea mays), millet (Panicum miliaceum) sorghum (Sorghum bicolour) and wheat (Triticum aestivum). J Food Sci Tech, 48 (6): 724-729.
Mubarak AE (2005). Nutritional composition and antinutritional factors of (Phaseolus aureus) as affected by some home traditional processes. Food Chemistry, 89(4):489-495
Khattak AB, ZEb A, Bibi N, Khattak SA (2007). Influenece of germination techniques on phytic acid and polyphenol content of chickpea (cicer arietinium L.) sprouts. Food Chemistry, 104(3): 1074-1079.
Kumar V, Sinha AK, Makar HPS, Becker K (2010). Dietary roles of phytate and phytase in human nutrition: a review. Food Chemistry, 120(4): 945-959.
Liang J, Han B-Z, Nout MJR, Hamer RJ (2009). Effect of soaking and phytase treatment on phytic acid, calcium, iron, and zinc in rice fractions. Food Chemistry, 115(3): 789-794.
Liang J, Han B-Z, Nout MJR, Hamer RJ (2008). Effects of soaking, germination and fermentation on phytic acid, total and in vitro soluble zinc in brown rice. Food Chemistry 110(4): 821-828.
Sokrab AM, Ahmed IAM, Babiker EE (2012). Effect of germination on antinutritional factors, total, and extrataqble mineral of high an low phytate corn (Zea mays L.) genotypes. J Saudi Soc Ag Sci 11:123-128.
Hotz C, Gibson RS, Temple L. A home-based method to reduce phytate content and increase zinc bioavailability in maize-based complementary diets. Int J Food Sci Nutr. 2001;52(2):133‐142.
Majzoobi M, Pashangeh S, Farahnaky A, Eskandari MH, Jamalian J. Effect of particle size reduction, hydrothermal and fermentation treatments on phytic acid content and some physicochemical properties of wheat bran. J Food Sci Technol. 2014;51(10):2755‐2761.
Afify A, El-Beltagi H, Abd El-Salam S, Omran (2011) Bioavailability of Iron, Zinc, Phytate and Phytase Activity during Soaking and Germination of White Sorghum Varieties. PLOS ONE 6(10): e25512.
Phytates
Kumar V, Sinha AK, Makar HPS, Becker K (2010). Dietary roles of phytate and phytase in human nutrition: a review. Food Chemistry, 120(4): 945-959.
Schlemmer U et al Phytate in foods and significance for humans: Food sources, intake, processing, bioavailability, protective role and analysis. Mol. Nutr. Food Res. 2009, 53, S330 –S375
Graf E and Eton JW (1990). Antioxidant functions of phytic acid. Free Radical Biol Med, 8(1):61-69.
Nuts and Health Benefits
Aune, D., et al., Nut consumption and risk of cardiovascular disease, total cancer, all- cause and cause-specific mortality: a systematic review and dose-response meta-analysis of prospective studies. BMC Med, 2016. 14(1): p. 207.
Afshin, A., et al., Consumption of nuts and legumes and risk of incident ischemic heart disease, stroke, and diabetes: a systematic review and meta-analysis. Am J Clin Nutr, 2014. 100(1): p. 278-88.
Nikodijevic C. et al. Nut consumption in a representative survey of Australians: a secondary analysis of the 2011–2012 National Nutrition and Physical Activity Survey. Public Health Nutrition. March 2020
Li, H., et al., Nut consumption and risk of metabolic syndrome and overweight/obesity: a meta-analysis of prospective cohort studies
and randomized trials. Nutr Metab (Lond), 2018. 15: p. 46.
Viguiliouk E et al Effect of tree nuts on glycemic control in diabetes: a systematic review and meta-analysis of randomized controlled dietary trials. PLoS One. 2014 Jul 30;9(7):e103376.
Flores-Mateo G et al Nut intake and adiposity: meta-analysis of clinical trials. Am J Clin Nutr. 2013 Jun;97(6):1346-55.
Mattes RD, Dreher ML. Nuts and healthy body weight maintenance mechanisms. Asia Pac J Clin Nutr. 2010;19(1):137-41.
Cassady BA, et al. Mastication of almonds: effects of lipid bioaccessibility, appetite, and hormone response. Am J Clin Nutr. 2009;89(3):794-800.
Casas-Agustench P, et al. Effects of one serving of mixed nuts on serum lipids, insulin resistance and inflammatory markers in patients with the metabolic syndrome. Nutr Metab Cardiovasc Dis. 2011 Feb;21(2):126-35.