The Paleo Diet® | Legumes and Nightshades
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Legumes and Nightshades

Both legumes and nightshades contain high concentrations of various anti-nutrients that increase intestinal permeability and can, therefore, cause a myriad of health concerns.

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The USDA My Plate guidelines recommend:

“Dry beans and peas are the mature forms of legumes such as kidney beans, pinto beans, black-eyed peas, and lentils. These foods are excellent sources of plant protein, and also provide other nutrients such as iron and zinc. They are similar to meats, poultry, and fish in their contribution of these nutrients. Many people consider dry beans and peas as vegetarian alternatives for meat.”

It is extremely misleading to evaluate the nutritional and health effects of beans and other legumes by simply comparing a few of their nutrients to other foods, as the USDA has done.

Before making such a claim, it is essential to determine how a food acts within humans. Beans are not good sources of either zinc or iron. In fact, these foods (even when fully cooked) are nutritional lightweights as a source of protein when compared to meat, fish, and other animal foods.

So, let’s take a closer look at how dry beans and peas compare to meats, poultry, fish, and eggs in terms of protein, iron, and zinc. On a caloric level, legumes contain far less protein than lean poultry, beef, pork, and seafood. Beans, peas, and other legumes contain 66 percent less protein than either lean chicken or turkey, and 61 percent less protein than lean beef, pork, and seafood.

The USDA also doesn’t tell you that our bodies don’t process bean and legume proteins nearly as efficiently as animal proteins. Legumes are chock full of anti-nutrients that impair the body’s ability to absorb and assimilate potential beneficial nutrients.

Without long term cooking or pressure-cooking, the anti-nutrients in legumes remain active and may disrupt gastrointestinal and immune function. As recently as 24 years ago imports of red kidney beans into South Africa were legally prohibited because of “their potential toxicity to humans.”

Nightshades are another recently introduced food group, from an evolutionary perspective. These include potatoes, tomatoes, green peppers, chili peppers, eggplants, and tomatillos. Nightshades have been consistently shown to increase intestinal permeability.

That said, we often make an exception for tomatoes. Because ripe red tomatoes have such low concentrations of α-tomatine, and because they are rich sources of vitamins, minerals, and other healthful nutrients, only people with an autoimmune disease or allergies should consider limiting their fresh ripe tomato intake.

In the U.S. we consume almost 230 pounds of nightshades per person on a yearly basis. These common foods have become such staples in our diets that few people rarely, if ever, consider that they are very recent additions to worldwide human nutrition.

On The Paleo Diet, we advise eliminating white/yellow potato consumption, and for autoimmune and allergy patients, we recommend caution when it comes to tomatoes, chili peppers, and eggplants.

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