The dark side of nuts; the missing link to why we’re still sick, fat and tired.


When I first went Paleo, I went a bit heavy on the nuts. I was eating trail mix, making “Paleo” approved desserts with assorted raw nuts, I was eating cashew “cheese”, nut butters, and I was drinking almond milk as my “milk” substitute. Then I felt something wasn’t right, instead of losing weight, I was gaining weight, my hair was falling out, I was cold all the time, I was experiencing muscle weakness and I was fatigued in the morning and totally drained by 7pm. I wasn’t eating any grain or sugar which wasn’t new for my “diet” but the only thing that I added back in was nuts.  As I was reading a blog about thyroid, I noticed that I had many of the symptoms associated with hypothyroid.  I asked myself, is there a link between nuts and thyroid? So I did some digging to find my answer.

Nuts contain phytic acid!

As a Paleo follower, I try to avoid phytic acid foods. Why? Because they have anti-nutrient components that deplete your body of vital vitamins and minerals. What foods contain phytic acid?

  • Most grains such as wheat, rye, oats, corn, millet, and brown rice.
  • Nuts and seeds
  • Legumes
  • Tubers – potatoes except sweet potatoes
  • Beans
  • Cocao (chocolate)

What is phytic acid? According to The Westin A. Price Foundation:

“Phytic acid is the principal storage form of phosphorus in many plant tissues, especially the bran portion of grains and other seeds. It contains the mineral phosphorus tightly bound in a snowflake-like molecule. In humans and animals with one stomach, the phosphorus is not readily bioavailable. In addition to blocking phosphorus availability, the “arms” of the phytic acid molecule readily bind with other minerals, such as calcium, magnesium, iron and zinc, making them unavailable as well. In this form, the compound is referred to as phytate.

Phytic acid not only grabs on to or chelates important minerals, but also inhibits enzymes that we need to digest our food, including pepsin, needed for the breakdown of proteins in the stomach, and amylase, needed for the breakdown of starch into sugar. Trypsin, needed for protein digestion in the small intestine, is also inhibited by phytates.”[1]

Grains, starches, sugars, legumes, beans and most tubers have an anti-nutrient factor plus these foods raise blood sugar, hence causing belly bloat or as Dr. William Davis calls it, “Wheat Belly”. So why do we (Paleo-lifers) incorporate so many nuts into our diet since we know they contain phytic acid? It’s because their convenient as a transportable food and serve as a good snack for those who are eliminating modern day fast foods. The problem is most of us don’t take the time to treat the nuts and seeds to ensure proper digestion.  This may come as a surprise to some but we can reduce the amount of phytic acid by soaking nuts, seeds, and grains in water, salt water, an acid (whey, lemon juice, and yogurt) or both. This will also allow you to digest nuts and seeds much better.

Grains such as rye are nutrient dense when lacto-fermented and turned into sour dough bread, but keep in mind, this will not omit gluten.  Getting back to nuts, when soaked this does reduce phytic acid plus it breaks down tannin [2]toxicity, but it does not eliminate either completely.  Keep in mind, this process is time consuming, hence the reason why we as Paleo-lifers tend to skip this vital process.

The link between nuts and thyroid

I believe there is a correlation between phytic acid, low iron and low thyroid. When we eat nuts, including peanuts (which is actually a legume), this is contributing to an iron deficiency because of the anti-nutrient factors. Iron is an important mineral that our body needs to carry oxygen to our blood cells, and regulates cell growth in our muscles. Needless to say, without iron, we become a limp, cold, weak pile of flesh. What I could have been experiencing was solely an iron deficiency. Then I stumbled across this by Byron Richards:

“A new study details the dire metabolic consequences of low iron status. It shows that low iron turns on genes in your liver and muscles that promote fat storage and cause abnormal blood sugar elevation – precisely what goes wrong with metabolism that leads to the metabolic syndrome. The consequence to thyroid metabolism is twofold. First, the inactive thyroid hormone, T4, is converted to the biologically active hormone, T3, mostly on cell membranes of liver cells. Hepcidin [hormone] is made in your liver and is produced excessively in response to high inflammation. Such inflammation will also damage liver cell membranes, thus reducing the conversion of T4 to T3. This is one main reason why inflammation of any type disturbs thyroid function.”[3]

This was mind blowing to me! By eating nuts, I was losing iron, by losing iron, I was inhibiting my thyroid function. Who knew?!

As soon as I went back to minimizing nuts, I felt better. Keep in mind, not everyone will share the same experience as I. It seems people who have a weak digestive system, permeable gut, and an auto immune disease experience the inability to digest nuts (even soaked)  more so than those with healthy guts. Another aspect of nuts is they may possess goitrogenic activity which means they hinder thyroid function. Goitrogenic foods are:

  • Broccoli
  • Bok choy
  • Cauliflower
  • Kale
  • Cabbage
  • Brussels
  • Sprouts
  • Mustard greens
  • Radishes
  • Strawberries
  • Peaches
  • Soy
  • Peanuts
  • Almonds
  • Cashews
  • Flaxseeds
  • Peanuts
  • Pumpkin seeds
  • Walnuts

As you can see its most cruciferous vegetables, nuts and seeds that are anti thyroid. Now, I’m not saying these foods are unhealthy, in fact, they’re very healthy but those with thyroid issues (Hashimotos, Graves disease, hypo/hyper thyroid) may want to minimize or stay away from goitrogenic foods altogether.

The upside to nuts

I know that I just threw a bunch of bad news at you. So, I want to clarify that nuts are a good healthy choice in moderation. Nuts are full of heart healthy qualities such as; magnesium, protein, omega 3 fatty acids, fiber, vitamin E, folate and the list goes on and on. Nuts aren’t a bad choice by any means. They’re way better for you than eating pretzels, candy or chips!

Another important key component to know is to take a look at the quality of nuts. Make sure to keep your nuts either in a dark cabinet or refrigerator. Don’t by nuts from store bins that have been sitting there for weeks on end and are going rancid do to over lighting, air and germs. Make sure to buy nuts that are in an air tight bag or even better from a local farmer who knows how to care for nuts properly.

In closing, we now know that too many nuts can make you nuts! We need to ease up on all of the nut butters, milks and trail mix. Like everything, nuts have to be consumed in moderation. They do indeed have great nutritional factors such as omega 3, protein, fiber and are heart friendly. But for those who have weak guts, auto-immune disease, thyroid issues, should stay away or minimize nut intake. Now that I’m (almost) nut free, personally, I feel better and all prior symptoms have resolved.




Nikki Jencen
Certified Holistic Health Coach, 32 years old, mother of 2 awesome kids, married to my college sweetheart for 9 beautiful years, I live in San Diego Ca, food fanatic, I'm crazy about all things healthy, I hate to exercise but do it anyway, I'm a workaholic (currently working on that), but the way I destress is by cooking and going to the grocery store (without kids!)...I'm a dreamer and non realist ~ I believe all things are possible.