Tannin and oxalate in foods are described to beresponsible for the deleterious effects that are related to the absorption ofnutrients and also give damage to certain part of the body.
Therefore, it isundesirable to have these anti-nutritional factors more than the upper limit.In order to control the consumption of these anti-nutritional factors, theknowledge of tannin rich food and oxalate rich food might be helpful. The examples of foods and beverages which are high intannin are tea, coffee and sorghum in cereals. Wine also contains tannin inaccordance to Puckette (2013), this anti-nutritional factor (ANF) gives the dryand astringent taste to the wine. The other tannin containing foods are millet,barley, dry beans, faba beans, peas, carobs, pigeon peas and winged beans. The fruitssuch as apples, bananas, blackberries, cranberries, dates, grapes,hawthornberries, peaches, pears, persimmons, plums, raspberries andstrawberries also stated as the tannin containing foods (Chung, Wei andJohnson, 1998). To reduce or neutralize the adverse effects of tannin on ironabsorption, it is advisable to add lemon to the tea.As stated by Harris and Coe (2013), spinach either cooked orraw, is the richest food source which high in oxalate as compared to the otherfoods.
Rhubarb which is a seasonal plant that is well-known in United Kingdomcontains 541 mg of oxalate per serving whereas Harris and Coe noted that ricebran and almonds contain 281 mg and 122 mg of oxalate respectively. The otherfood sources which are high in oxalate are soy nuts and beans, soy flour, cashews,sesame seeds, beets, cocoa powder, okra, raspberries and cornmeal. However, itdoes not mean all of these listed foods are need to be avoid. Fortunately,these kind of foods can be consumed in a safe manner.
For oxalate, in order toprevent the stone formation, it is good toconsume it less than 100 mg and less than 50 mg of oxalate is an idealrecommendation (Harris and Coe, 2013).