Beans, Beans, good for your heart…
To quote a favorite saying among male classmates when I was in second grade. This quote claims that beans are good for your heart, among other things.
Not that we can put any stock in a childhood saying, of course, but the general consensus in the health community is that beans are, in general, a “health” food and that when combined with rice, form a perfect protein for vegetarians.
Beans show up in some form in many different cultures and countries, though preparation methods vary vastly. Americans, for our part, get most of our bean consumption from soy and soy products.
Peanuts, technically also a legume and not a nut, also make up a substantial part of our bean consumption, and are also a rapidly rising allergy, especially among children.
What’s In A Bean?
Beans contain a lot of soluble fiber, protein, carbohydrates, folate and iron. They also contain Lectins, which are also present in high amounts in grains. Because of their protein content, beans (legumes) often get a primary role in the diet of vegetarians, though not without cost.
The lectins in legumes are an important protective measure for the bean plant, and a potentially harmful one for humans. Before the dawn of genetically modified disease resistant soybeans (gee, thanks Monsanto) and their corresponding toxic pesticides and herbicides, legume plants were actually quite able to defend themselves.
What do Lectins Do?
Lectins are specific proteins that bind to carbohydrates, and exist in plants in varying levels as a protective mechanism. When animals who are not adapted to consuming particular types of lectins eat them, they will experience pain or death.
This reaction is not absent in humans, as I mentioned when I explained why grains can be so harmful. As Wikipedia explains, one example of lectin reaction in humans:
Some kinds of raw beans and especially red and kidney beans, contain a harmful toxin (the lectin Phytohaemagglutinin) that must be destroyed by cooking. A recommended method is to boil the beans for at least ten minutes; undercooked beans may be more toxic than raw beans. Cooking beans in a slow cooker, because of the lower temperatures often used, may not destroy toxins even though the beans do not smell or taste ‘bad’ (though this should not be a problem if the food reaches boiling and stays there for some time).
At the extreme, lectins are potent enough to be a biological warfare agent as in the case of ricin. Ricin is a lectin isolated in the castor oil bean and it acts on certain protein cells, allowing the ricin to enter the cell and prevent protein synthesis, eventually leading to cell death.
Obviously, some lectins have more toxic effects than others, as evidenced by the example above, but all lectins have some effect on the body. This is the reason that grains, beans, and other lectin containing foods cannot be eaten raw.
Lectins are capable of harming the lining of the intestines, especially the microvilli. This happens when the lectins bind to the protein receptors in the intestinal lining, causing damage.
When the intestines are damaged, lectins, and the foods that they bind to, can pass through the intestinal wall and into the blood stream. These sticky molecules can then wreak havoc in the bloodstream.
Once lectins are floating around in the bloodstream, they can bind to any carbohydrate containing protein cells, including insulin and leptin receptors, desensitizing them. Without proper insulin and leptin function, problems like diabetes and metabolic syndrome can emerge. It is speculated that lectins may cause insulin and leptin resistance, two major factors in obesity and diabetes. As Whole Health Source explains:
What is not so speculative is that once you’re leptin-resistant, you become obese and insulin resistant, and at that point you are intolerant to any type of carbohydrate. This may explain the efficacy of carbohydrate restriction in weight loss and improving general health.
Lectin may cause leptin resistance, affecting its functions (signal have high levels of leptin and several effects gathering to protect from lipid overload), as indicated by studies on effects of single nucleotide polymorphisms on the function of leptin and the leptin receptor.
Such leptin resistance may translate into diseases, notably it could be responsible for obesity in humans who have high levels of leptin.
Lectins also have the potential to bind to any carbohydrate containing tissue in the body, from the thyroid to the heart. (Maybe beans aren’t so good for the heart after all!). My personal theory is that sticky particles and pre-digested food floating around in the bloodstream does much more to clog arteries than slippery saturated fats, which get the bad rap!
So, lectins can contribute to disease and obesity when they pass through the intestinal wall and float through our bloodstream with other parts of pre-digested food. Personally,I’m not a big fan of the idea of partially digested food floating around in my blood, so is there a solution?
Reducing Lectin in Beans and Grains
I certainly don’t want to let beans take all the heat here! Grains contain just as high of levels of lectins and can wreak just as much havoc, if not more.
All plants, in fact, contain lectins in varying amounts. Grains and beans (especially soybeans and peanuts) have especially high concentrations, along with nuts, pasteurized dairy, and genetically modified foods.
The harmful effects of lectins (and phytic acid) can be mitigated some by using traditional methods of perpetration, like sprouting, fermenting, and soaking, though even these do not remove the lectins completely. Unfortunately, these methods are rarely practiced anymore, and grains in the processed forms we typically consume are little lectin powerhouses.
Over time, these lectins can cause serious damage to the intestinal lining and eventually cellular damage within the body.
What Level of Lectin Consumption is Safe?
This is a difficult question with no single answer. Certainly, if foods containing high levels of lectins are going to be consumed, traditional methods like soaking, fermenting, and sprouting should be used to minimize the lectin content.
My personal recommendation is the get rid of the highest sources of lectins and reduce the other sources if possible. From Wikipedia:
Foods with high concentrations of lectins, such as beans, cereal grains, seeds, and nuts, may be harmful if consumed in excess in uncooked or improperly cooked form. Adverse effects may include nutritional deficiencies, and immune (allergic) reactions. Possibly, most effects of lectins are due to gastrointestinal distress through interaction of the lectins with the gut epithelial cells. A recent in vitro study has suggested that the mechanism of lectin damage may occur by interfering with the repair of already-damaged epithelial cells.
Personally, I avoid the grains (and legumes except rare occasions), soak nuts overnight, and trust that the much lower levels in other plants won’t harm my intestines too much. Removing all processed and commercially prepared foods will remove the worst offenders: grains and soy.
If you are overweight or attempting to lose weight, a more stringent avoidance of lectins might be helpful. Since lectins can bind to leptin and insulin receptors, they can increase resistance to carbohydrates and cause weight gain or inability to lose weight.
For many, avoiding lectins, especially for a year or so, can help heal the intestinal lining, and facilitate weight loss, reduction of allergy symptoms, and other health improvements.
So, I guess second grade logic isn’t so solid after all…. beans aren’t necessarily good for the heart, though other parts of the saying still ring true!
Do you eat beans? If so, what kind(s)? Share below!