Is activating a vital step?

Transcription

1 Is activating a vital step? Lisa Yates all articles by this author Is it really necessary to soak grains, nuts and seeds to reduce the impact of phytates? A RECENT trend is activating grains, nuts and seeds by soaking them for hours to start the germination process and reduce the impact of phytates on the absorption of minerals. Phytates are the salts of phytic acid (myo-inositol-hexakis dihydrogen phosphate or inositol hexaphosphate). This is a storage compound which contains calcium, magnesium and phosphate and is found in plant seeds. During germination, phytates are broken down by phytase enzymes and the minerals released are used by the plant for the developing shoot and root. 1 Nutritional deficiency For some time phytate has been considered a negative compound an anti-nutrient for humans because it also binds to minerals such as iron and zinc, preventing their absorption in the intestine. Under certain circumstances this may result in nutrient deficiencies. However, it is now known that by the time phytates reach the large intestine, they have been largely metabolised with the assistance of bacteria in the gut. 1,2 This is especially so for people following vegetarian diets. 2 Phytates can also be reduced by food processing, i.e. soaking/malting where natural phytase enzymes break down phytate, and through fermentation which generates lactic acid, increasing phytase activity and thereby reducing phytate. 1 Recent research, however, has revealed that phytates have valuable health-promoting properties

2 (see box, below). Daily intake estimates of phytate and other inositol phosphates in Western diets varies from 0.3g to 2.6g, and around the world range from 0.18g per day to 4.57g/day. 1 Phytate levels are higher in vegetarian diets and especially in developing countries where traditional diets rely heavily on grains and legumes as staple foods. For those consuming a varied diet, nutrient deficiencies as a result of phytates are rare, but in developing countries where balanced diets are more difficult to achieve, the effect of phytates on mineral malabsorption is more apparent. 1 Food sources Phytates are found in wholegrains, legumes, nuts and seeds. In grains, phytates are found in the bran husk and germ, while the endosperm (carbohydrate) is

3 mostly free of phytates. In legumes, phytates are mainly found in the protein component of the seed (Table 1). 1 These large phytate concentration ranges not only reflect the vast number of botanical varieties of seeds and their growing and environmental conditions but also the different stages of seed development. 1 Legumes, wholegrains, nuts and seeds are valuable whole-plant foods rich in a variety of nutrients with clear health benefits. While phytates may be present in the bran, husk or coat covering the seed, this part is also rich in fibre and prebiotics. Health benefits Diets rich in these whole foods reduce the risk of heart disease, cholesterol, diabetes, overweight

4 and cancer among others For instance, consuming 30g of nuts a day can reduce the risk of heart disease, diabetes, lower cholesterol and help manage weight Similarly, legumes and wholegrains have also been shown to reduce the risk of these diseases, especially colorectal cancer It s possible one of the mechanisms explaining how these plant foods provide such advantage is their phytate content. High iron has been found to impact bowel cancer development so reducing iron absorption of animal protein eaters may be an advantage. 40 To demonise phytates based on their negative impact on mineral bioavailability alone means ignoring the evidence for their health benefits. Australians following well-balanced diets do not need to activate their grains and seeds to reduce phytates. As Australian bowel cancer rates are high, 41 phytates may provide the very protection we need to avoid this cancer developing. Disclosure: Lisa Yates consults to the Australian Tree Nut Industry. References 1. 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 S Markiewicz LH et al Diet shapes the ability of human intestinal microbiota to degrade phytate--in vitro studies. J Appl Microbiol Jul;115(1): Graf, E., Empson, K. L., Eaton, J.W., Phytic acid A natural antioxidant, J. Biol. Chem. 1987, 262, Zajdel A et al Phytic acid inhibits lipid peroxidation in vitro. Biomed Res Int 2013;2013: Shamsuddin, A. M., Inositol phosphates have novel anticancer function, J. Nutr. 1995, 125, 725S 732S. 6. Fox CH, Eberl M. Phytic acid (IP6), novel broad spectrum anti-neoplastic agent: a systematic review. Complement Ther Med 2002; 10: Karmakar S et al Molecular mechanism of inositol hexaphosphate-mediated apoptosis in human malignant glioblastoma T98G cells. Neurochem Res Dec;32(12): Bozsik A et al Molecular mechanisms for the antitumor activity of inositol hexakisphosphate (IP6). Cancer Genomics Proteomics Jan-Feb;4(1):43-51.

5 9. Graf E, Eaton JW Suppression of colonic cancer by dietary phytic acid. Nutr Cancer. 1993;19(1): Kapral M et al Induction of the expression of genes encoding TGF-beta isoforms and their receptors by inositol hexaphosphate in human colon cancer cells. Acta Pol Pharm Mar-Apr;70(2): Kapral M et al The effect of inositol hexaphosphate on the expression of selected metalloproteinases and their tissue inhibitors in IL-1β-stimulated colon cancer cells. Int J Colorectal Dis Nov;27(11): Wawszczyk J et al The effect of phytic acid on the expression of NF-kappaB, IL-6 and IL-8 in IL-1beta-stimulated human colonic epithelial cells. Acta Pol Pharm Nov-Dec;69(6): Norhaizan ME et al Antioxidant and cytotoxicity effect of rice bran phytic acid as an anticancer agent on ovarian, breast and liver cancer cell lines. Malays J Nutr Dec;17(3): Grases F et al Urinary phytate (Myo-inositol hexaphosphate) in healthy school children and risk of nephrolithiasis. J Ren Nutr Jul;24(4): Prieto RM et al Effects of Mediterranean diets with low and high proportions of phytate-rich foods on the urinary phytate excretion. Eur J Nutr Sep;49(6): Saw NK et al Effects of inositol hexaphosphate (phytate) on calcium binding, calcium oxalate crystallization and in vitro stone growth. J Urol Jun;177(6): Grases F et al Phytate (Myo-inositol hexakisphosphate) inhibits cardiovascular calcifications in rats. Front Biosci Jan 1;11: Croze ML et al Potential role and therapeutic interests of myo-inositol in metabolic diseases. Biochimie Oct;95(10): Hanson LN et al Effects of soy isoflavones and phytate on homocysteine, C-reactive protein, and iron status in postmenopausal women. Am J Clin Nutr Oct;84(4): Kim JN et al Phytic acid and myo-inositol support adipocyte differentiation and improve insulin sensitivity in 3T3-L1 cells. Nutr Res Aug;34(8): Fardet A et al Plant-based foods as a source of lipotropes for human nutrition: a survey of in vivo studies. Crit Rev Food Sci Nutr. 2013;53(6): López-González AA et al Protective effect of myo-inositol hexaphosphate (phytate) on bone mass loss in postmenopausal women. Eur J Nutr Mar;52(2): López-González AA et al [The influence of consumption of phytate on the bone mass in postmenopausal women of Mallorca]. Reumatol Clin Jul-Aug;7(4): Lopez-Gonzalez AA et al Phytate levels and bone parameters: a retrospective pilot clinical trial. Front Biosci (Elite Ed) Jun 1;2: López-González AA et al Phytate (myo-inositol hexaphosphate) and risk factors for

6 osteoporosis. J Med Food Dec;11(4): Anekonda TS et al Phytic acid as a potential treatment for alzheimer s pathology: evidence from animal and in vitro models. J Alzheimers Dis. 2011;23(1): Kelly JH Jr, Sabaté J Nuts and coronary heart disease: an epidemiological perspective. Br J Nutr Nov;96 Suppl 2:S Sabaté J, Oda K, Ros E. Nut consumption and blood lipid levels: a pooled analysis of 25 intervention trials. Arch Intern Med May 10;170(9): Jiang R et al Nut and peanut butter consumption and risk of type 2 diabetes in women. JAMA Nov 27;288(20): Jackson CL, Hu FB Long-term associations of nut consumption with body weight and obesity. Am J Clin Nutr Jun 4;100(Supplement 1):408S-411S. 31. Mudryj AN et al Nutritional and health benefits of pulses. Appl Physiol Nutr Metab Jun 13:1-8. [Epub ahead of print] 32. Bouchenak M, Lamri-Senhadji M Nutritional quality of legumes, and their role in cardiometabolic risk prevention: a review. J Med Food Mar;16(3): Flight I, Clifton P Cereal grains and legumes in the prevention of coronary heart disease and stroke: a review of the literature. Eur J Clin Nutr Oct;60(10): Seal CJ Whole grains and CVD risk. Proc Nutr Soc Feb;65(1): Belobrajdic DP, Bird AR The potential role of phytochemicals in wholegrain cereals for the prevention of type-2 diabetes. Nutr J May 16;12: Venn BJ, Mann JI. Cereal grains, legumes and diabetes. Eur J Clin Nutr Nov;58(11): Kyrø C et al Intake of whole grains from different cereal and food sources and incidence of colorectal cancer in the Scandinavian HELGA cohort. Cancer Causes Control Jul;24(7): Aune D et al Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies. BMJ Nov 10;343:d Clemente A, Arques Mdel C Bowman-Birk inhibitors from legumes as colorectal chemopreventive agents. World J Gastroenterol Aug 14;20(30): Qiao L, Feng Y Intakes of heme iron and zinc and colorectal cancer incidence: a meta-analysis of prospective studies. Cancer Causes Control Jun;24(6): Australian Government Cancer Australia, Tags:, Cancer, Cardiovascular, Diabetes, Nutrition, Obesity, Research, Stroke

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