Potato Vs. Grains And Phytic Acid

Phytic acid, called phytate in the salt form, serves as the phosphorus source for the germination and growth of plants. Phytic acid is often referred to an anti-nutrient because it chelates and decreases the body's ability to absorb essential nutrients from foods containing phytic acid, including grains and potatoes.

Grain

As much as 85 percent of the total phosphorous content of grain is phytic acid.Although grain is a good source of nutrients, the digestibility and solubility of many minerals, proteins and carbohydrates are inhibited due to the phytic acid content. Phytase neutralizes phytic acid, but the human body lacks this digestive enzyme needed to free phosphorus. Grains contain some phytase -- rye contains the most phytase; wheat contains more than rice. Sprouting grain, soaking or souring it in a warm environment, as when making sourdough, activates phytase and may reduce or even eliminates phytic acid.

Potatoes

Potatoes contain less phytate than most grains depending on the variety and soil fertility. Phytic acid in potatoes increases with maturity. New potatoes contain less phytic acid by weight than those harvested at a later stage of development. Boiling, baking or microwaving russet potatoes showed no decrease in phytate content in a study published in the "Journal of Food Composition and Analysis" in 2004. French fries, potato chips and dehydrated potato flakes were shown to retain much of their phytates.

Nutrient Absorption

Phytic acid in grains and potatoes reduces the body's ability to absorb and digest minerals such as calcium, zinc, iron and magnesium, and protein. The effect is not only in the food containing phytic acid, but also in food you eat with it. The Swiss Federal Institute of Technology in Zurich evaluated the effect of phytic acid on the absorption of magnesium in the body. Healthy adults, given whole wheat bread, were found to have lower magnesium absorption with the addition of phytic acid. Results, published in the "American Journal of Clinical Nutrition," March 2004, showed that impaired mineral absorption was dose-dependent in amounts similar to that naturally found in whole-meal and brown bread.

Health

Mineral deficiencies resulting from a high consumption of phytate-containing foods can cause many health issues, including skin problems, decreased appetite and mental exhaustion. People especially at risk are those with low mineral intakes, such as children and people living in developing countries where the primary food is grain-based. Phytate-induced zinc deficiencies may lead to anemia, reduced testosterone production, altered immune function and poor infant development. Inhibited ability to absorb calcium may increase the risk of rickets and bone softening. Laura Johnson Kelley from Cornell University in New York says that, as human populations began to consume grains as a staple diet in Europe, skeletal abnormalities and celiac disease increased.