Tannin and oxalate in foods are described to be
responsible for the deleterious effects that are related to the absorption of
nutrients and also give damage to certain part of the body. Therefore, it is
undesirable to have these anti-nutritional factors more than the upper limit.
In order to control the consumption of these anti-nutritional factors, the
knowledge of tannin rich food and oxalate rich food might be helpful.
The examples of foods and beverages which are high in
tannin are tea, coffee and sorghum in cereals. Wine also contains tannin in
accordance to Puckette (2013), this anti-nutritional factor (ANF) gives the dry
and 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 fruits
such as apples, bananas, blackberries, cranberries, dates, grapes,
hawthornberries, peaches, pears, persimmons, plums, raspberries and
strawberries also stated as the tannin containing foods (Chung, Wei and
Johnson, 1998). To reduce or neutralize the adverse effects of tannin on iron
absorption, it is advisable to add lemon to the tea.
As stated by Harris and Coe (2013), spinach either cooked or
raw, is the richest food source which high in oxalate as compared to the other
foods. Rhubarb which is a seasonal plant that is well-known in United Kingdom
contains 541 mg of oxalate per serving whereas Harris and Coe noted that rice
bran and almonds contain 281 mg and 122 mg of oxalate respectively. The other
food sources which are high in oxalate are soy nuts and beans, soy flour, cashews,
sesame seeds, beets, cocoa powder, okra, raspberries and cornmeal. However, it
does 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 to
prevent the stone formation, it is good to
consume it less than 100 mg and less than 50 mg of oxalate is an ideal
recommendation (Harris and Coe, 2013).