Paleo Diet Not Working? Exploring Sulfur Intolerance As A Possible Connection

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In recent years, the Paleo Diet has received considerable attention as a means for improving overall health. The anecdotal evidence for patient improvement on a Paleo, or the more restrictive Autoimmune Paleo (AIP) diet, is abundant.1-5

What you hear less frequently is that some people experience negative effects, or a worsening of symptoms with a Paleo or AIP diet. It seems counterintuitive that eating a healthy diet high in cruciferous greens such as kale, cabbage, and broccoli, in combination with high quality proteins and fats, can make you feel worse. Why is that the case? One hypothesis is that when people do not feel better on a Paleo or AIP diet, they may have an issue with processing sulfur.

Sulfur is essential for various physiological functions in our bodies and is typically beneficial to our health. For instance, sulfur can greatly improve your body’s ability to detoxify, as well as aid your immune system in reacting appropriately to dangerous pathogens. Sulfur is also important for hormone and water regulation, microbiome balance in your gut, and healthy connective tissue support.6

When sulfur starts accumulating in your body, it can lead to a myriad of seemingly unexplainable symptoms and imbalances. Excess sulfur has been associated with dysbiosis, where it enables pathogenic bacteria in your gut to grow to unhealthy levels. It can also deplete BH4, which disrupts the balance of important brain chemicals, such as dopamine and serotonin. Anxiety, depression, headaches, and other adverse side effects commonly occur when these chemicals are out of balance.7

One reason why you may have high sulfur levels is that you are eating excessive amounts of sulfur through foods or supplements. However, a more likely reason is that you may have a defect in your transsulfuration pathway leading to an inability to correctly process sulfur. The cause of this defect may be toxic exposure to heavy metals and pesticides such as aluminium, cadmium, and glyphosate. Another cause may be your body lacking nutrients necessary to process sulfur such as B6 and molybdenum. Based on my clinical experience, the most common offenders are genetic mutations affecting the transsulfuration pathway.8

So how do you know if you may have a problem with processing sulfur?

Some key considerations are:

  • Have you ever experienced reactions to sulfa-based drugs?
  • Do you have a history of asthma and shortness of breath?
  • Are you bloated, gassy, and/or experiencing abdominal pain?
  • Do you have a history of skin problems such as hives, rashes, acne, eczema, psoriasis, or dermatitis?
  • Do you often experience headaches, brain fog, anxiety or tend towards explosive anger?
  • Do you experience flushing, sweats, or tend to have hot hands and feet?
  • Do your symptoms worsen when you consume alcohol? Or when you eat cruciferous greens and other sulfur containing foods such as garlic, onions, and eggs?

If your answer to some of these questions is ‘yes,’ then you may have trouble processing sulfur and should consider taking the following steps below.

Step 1: Decrease High Sulfur Foods

I typically recommend my patients to eliminate the following high sulfur foods from their diet for a minimum of two weeks:

  • Garlic
  • Onions
  • Cabbage
  • Kale
  • Collard Greens
  • Cauliflower
  • Brussel Sprouts
  • Broccoli
  • Arugula
  • All dried fruit
  • Vinegar
  • Alcoholic beverages
  • Dairy and Eggs
  • Soy
  • High amounts of lean animal products (higher fat meats and fish are preferable as they contain less sulfur)

Step 2: Avoid Sulfur-Containing Supplements

In conjunction with adjusting your diet, make sure to stop taking the following supplements:

  • Garlic Extracts
  • N-Acetylcysteine (NAC)
  • Glutathione
  • Taurine
  • Cysteine
  • Methionine
  • Chondroitin Sulfate and MSM
  • Milk Thistle
  • Alpha Lipoic Acid
  • Epson Salt Baths

Step 3: Support Your Transsulfuration Pathway

The following supplements are helpful in supporting your sulfur pathway:

  • B12 (in the form of hydroxocobalamin)
  • Molybdenum (use liquid version and start very slowly)
  • Calcium/Magnesium Butyrate

Step 4: Identify The Root Cause

As discussed above, you may have some genetic mutations that inhibit your body from processing and eliminating sulfur efficiently. I recommend that you seek out a qualified healthcare practitioner that can help you identify any genetic defects. Some key genetic markers to look out for are:

  • SUOX
  • NOS

Your practitioner may choose to assess your sulfur levels through urinary testing and may further recommend testing for heavy metals, chemical sensitivities, and dysbiosis. In some cases, the dietary recommendations may only have a slightly beneficial effect. In this instance, I recommend that you additionally consider avoiding foods high in thiols (compounds containing bivalent sulfur).9 Once you have established a clear picture on your current health status, your practitioner will be able to implement targeted treatment protocols to address the root cause of your problem.


Lindeberg S, et al. A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease.Diabetologia, 2007. []
Osterdahl M, et al. Effects of a short-term intervention with a paleolithic diet in healthy volunteers. European Journal of Clinical Nutrition, 2008. []
Jonsson T, et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovascular Diabetology, 2009. []
Frassetto, et al. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. European Journal of Clinical Nutrition, 2009. []
Ryberg, et al. A Palaeolithic-type diet causes strong tissue-specific effects on ectopic fat deposition in obese postmenopausal women. Journal of Internal Medicine, 2013. []
Marcel E Nimni, Bo Han and Fabiola Cordoba. Are we getting enough sulfur in our diet? Nutrition & Metabolism 2007. []
Greg Nigh, ND, LAc Maria Zilka, NTP. Identifying & Addressing Sulfur Reactions and Their Related Symptoms. Biotics Research Seminar, 07/20/2015.
Clark. “Sulphur Foods (Thiols).” Livingnetworkcoza. Web. 8 Sept. 2015. []