Debugging Anti-Nutritional Factors in Beans

Posted: July 17, 2016

Beans, Beans, the magical fruit that makes you toot.  Beans may in fact be the best thing to ever grow, ever, but beans have been brought to shame.  There has been news traveling around that beans are in fact more harmful than good.  This had to be pondered by not only myself but other fart loving, bean eaters. 

            The first claim that had been made was about this mysterious phytic acid.  To the normal population that means nothing, but throw some radical claims behind it and now it means everything; everything bad.  Phytic acid is found in many plant seeds, especially in legumes, the category beans falls into.  Some studies have linked consumption of phytic acid to decreased absorption of minerals such as iron, zinc, and calcium (1).  However this is only a concern if you do not eat meat.  Meat eaters are not at risk for mineral deficiencies caused by phytic acid (2).  If in fact you are living in a developing country or vegetarian and your diet consist largely of legumes and or grains, you may have some concern (3).  But if that is the case, there are ways to prevent any deficiencies.  Simply soak or ferment the beans you eat. 

            The second claim you may have heard is about Lectins.  These are proteins found in legumes.  Some claim that these proteins resist digestion and affect the lining of the intestinal tract.  The one Lectin in particular that the public has heard the most about is Phytohemagglutinin.  This lectin is found in all beans but is found in higher concentrations in red kidney beans.  Phytohemagglutinin is toxic in high amounts, and there have been incidents of poisoning.  That was due to the consumption of raw red kidney beans or beans that weren’t cooked correctly (4). What does that mean? It means soak your beans for 24 hours, and cook them at high temperatures for at least 10 minutes.  This process will degrade Phytohemagglutinin and other Lectins (5).

            Saponins are other components associated with beans being harmful.  Saponins are found in a variety of plants and are resistant to digestion.  These nutrients may affect the cells lining the gut, which may increase intestinal permeability (6).  This is more commonly known as leaky gut.  These claims are purely speculation and no credible studies have been published. 

            These aforementioned components in legumes have been labeled “anti- nutrients” in order to persuade consumers away from them.  These so called “anti-nutrients” can be avoided by proper preparation and cooking methods.  Soak your beans overnight, especially kidney beans, and cook them at high temperatures (100° C).  Similar to meats, if not cooked correctly or raw, they can be harmful. 

The benefits and taste far outweigh the “anti- nutrient” claim.  The nutritional value of beans consists of high amounts of protein, fiber, carbohydrates, iron, folate, magnesium, and potassium.  They have smaller amounts of Vitamins B1, B3, B5, B6, phosphorus, zinc, copper, and manganese.  They are also relatively low in calories (around 200-300 cal/kg) depending on the bean (7).   

Eat up people.  Beans are highly nutritious and delicious.  They make great food options for any diet and any occasion.  No matter what the season, sporting event, or holiday make sure you have beans at the table.  Warning, they may cause very gaseous buildups which result in, hilarious yet foul smelling flatulent. 

The above article was written by AJ Rafter. AJ is a certified Strength and Conditioning Specialist at Compete Sports Performance and Rehab and is currently working on his Masters Degree in Food Science at Chapman University.


1.     Lopez  H.W, Leenhardt F. , Charles Coudray C., Remesy C. “Minerals and phytic acid interactions: is it a real problem for human nutrition?” International Journal of Food Science & Technology. Volume 37, Issue 7, pages 727–739, October 2002.

2.     Sandström B, Almgren A, Kivistö B, Cederblad A. “Effect of protein level and protein source on zinc absorption in humans.” Journal of Nutrition. Volume 119, Issue 1, pages 48-53, January 1989.

3.     Hunt JR. “Bioavailability of iron, zinc, and other trace minerals from vegetarian diets.” American Journal of Clinical Nutrition. Volume 78, Supplement 3, pages 633S- 639S, September 2003.

4.     Rodhouse JC,  Haugh CA, Roberts D, Gilbert RJ. “Red kidney bean poisoning in the UK: an analysis of 50 suspected incidents between 1976 and 1989.” Journal of Epidemiology and Infection. Volume 105, Issue 3, Pages 485- 491, December 1990.

5.     Sharon N,  Lis H. “Legume lectins--a large family of homologous proteins.” Journal of the Federation of American Societies for Experimental Biology. Volume 14, Pages 3198-3208, November 1990.

6.     Johnson, I. T., Gee, J. M., Price, K., Curl, C., & Fenwick, G. R. (1986). Influence of Saponins on Gut Permeability and active nutrient transport in vitro. Journal of Nutrition, 116(11), 2270-2277.

7.     Self Nutrition Data. Nutrition Facts Lentils, mature seeds, cooked, boiled, without salt. September 17, 2015.