One of the most confusing “no-no’s” of the paleo diet is beans and legumes. Most of us have grown up learning hat beans are healthy for us because of their fiber and protein content, and many vegetarians and vegans rely on them as a protein source. But, according to the founding fathers of the paleo diet, legumes are no good. But what exactly is a legume, and why can’t you eat it? (Hint: if you read on, you’ll see that you can).
What Are Legumes?
According to Merriam Webster, legumes are “a type of plant (such as a pea or a bean plant) with seeds that grow in long cases (called pods)”. The fruits and seeds of these plants that we eat are also known as legumes. The legume family includes beans, peas, green beans, and peanuts.
Why Aren’t They Paleo?
There are a few reasons the paleo community excludes legumes. A few of the big ones include:
1. They contain phytic acid/phytates, which are “anti nutrients” that block the absorption of vitamins and minerals
2. They contain lectins, a class of proteins thought to cause “leaky gut” in the shorter term and problems like arthritis and poor vitamin/mineral absorption in the longer term
3. Cavemen didn’t eat them
Why They’re Not The Devil
Sadly, a lot of the paleo blogs that explained why legumes aren’t paleo were written with a lot of doom and gloom. I closed out my Safari tab thinking my body was going to self combust if I ate a black bean tomorrow. But then I dug a little deeper and found out it’s not so black and white.
1. Phytic acid is the stored form of phosphorous. Phytic acid is often called an “anti nutrient” because it binds minerals in the digestive tract, forming phytate (a mineral bound to phytic acid). This does happen, although phytic acid can be broken down by several processes including fermentation, cooking, soaking, and sprouting. However, despite this drawback, there are some other benefits to phytic acid. When it binds minerals in the digestive tract, it reduces the formation of free radicals, making it like an antioxidant. It can also bind heavy metals (like lead or mercury), reducing their accumulation in the body. You can read this article from a great group of nutritionists and scientists at Precision Nutrition to see more benefits of phytic acid.
2. Lectins are a class of protein that binds to sugars. In humans, lectins facilitate cell to cell contact, and in plants they often act as a protection or insecticide. Lectin poisoning is a thing, if you happen to enjoy raw beans. When food passes through our guts, it causes minor damage that is usually easily repaired by the body. However, lectins can cause damage when they slow this repair. When that happens, the digestive lining doesn’t function as well as it should, allowing some undesirable substances that would normally be contained in the gut to pass to the body, and inhibiting the absorption of certain good substances like vitamins and minerals. This is what is referred to as “leaky gut”. If you eat too many lectins, your body will respond by trying to evacuate the gut – i.e. fun symptoms like diarrhea, cramping, vomiting, etc. Gut damage from lectin overdoes can also cause immune responses like joint pain and skin rash. However, it’s not all doom and gloom. Like phytic acid, lectins can also be neutralized by processes like soaking and sprouting.
3. Actually, cavemen may have eaten legumes! A study in the journal Proceedings of the National Academy of Sciences of the United States of America looking at tooth decay in prehistoric skeletons found that neanderthals ate a diverse diet of available plants, including legumes. Although this study was in Neanderthals, it is widely thought that Homo Sapiens enjoyed am ore diverse diet than Neanderthals, meaning it’s likely they would have eaten legumes as well. I mean, it makes sense to me that if the could figure out tools and fire, they could figure out soaking, sprouting and cooking.
What Should You Do?
As I love to say in almost all of my blog posts, the impact of choosing to eat these particular foods will depend on a variety of factors, including your genetics, your current state of health, and how much of them you eat. I don’t think legumes should be entirely avoided, but I also don’t think you should eat beans and peanuts at every meal either. That would result in leaving out a lot of other foods with important nutrients – like grass-fed meats and eggs, or vegetables, fruits, organic dairy, etc – that you might otherwise enjoy. There are real concerns about lectins in very high doses (which is why they don’t offer to put Castor beans in your burrito at Chipotle), but a cup of green beans with dinner a couple of nights a month or the occasional hummus and carrots snack isn’t going to give you leaky gut unless you happen to be very sensitive to lectins (research shows individuals on the autism spectrum and those with Crohn’s disease tend to be more sensitive to lectin damage). If legumes are causing a problem for your body, more likely than not your body will inform you of this fact in the form of stomach discomfort, gas, joint pain, etc.
What are your thoughts? Do you eat legumes? Avoid them?