Sulfur is the third most abundant mineral (after calcium and phosphorus) in the human body and is critical to maintaining healthy cellular function . We get sulfur almost entirely from protein sources, but only two amino acids, methionine and cysteine, contain sulfur. We might also get extra sulfur from taking certain supplements like methylsulfonylmethane (MSM) or alpha-lipoic acid.
As with any mineral or nutrient, too much of a good thing can become detrimental to our health. Some people with gut issues like SIBO or unexplained digestive symptoms like bloating and abdominal pain are sensitive to foods high in sulfur or supplements containing high levels of sulfur.
In this article, we’ll review why foods with high amounts of sulfur — such as cruciferous vegetables, legumes, red meat, and more — can cause digestive issues for some people, what foods are high in sulfur, how to go on a temporary low-sulfur diet, and other ways to lower sulfur levels in the human body.
What Is Sulfur Intolerance?
Sulfur intolerance is thought to occur when too much sulfur builds up in the body, causing you to react with digestive and other systemic symptoms when you consume sulfur-rich foods.
While there is very little research on sulfur intolerance, the symptoms are thought to include:
- Brain fog
- Excessive gas that smells like rotten eggs
- Abdominal pain and bloating
- Swollen and stiff joints
- Asthma or difficulty breathing
- Skin irritation, such as hives, itching, or flushed skin
- Puffiness, swelling, or water-weight gain
How Do I Know If I Have a Sulfur Intolerance?
The symptoms above may also be signs of other kinds of conditions, gut imbalances, or food sensitivities. So, even if you have many or all of the symptoms listed above, you still can’t say for sure that you have a sulfur intolerance or sensitivity until you try a low-sulfur elimination diet and reevaluate your symptoms.
Fortunately, this diet is short-term and you should be able to tell whether your symptoms have changed within a few days, but you can stay on the low-sulfur diet for up to a week. If your symptoms have not improved after seven days, sulfur is probably not the root cause of your symptoms.
For now, there isn’t really a good diagnostic test to identify whether you’re sensitive to foods high in sulfur, so trying a low-sulfur diet is your best bet. If you find that the low-sulfur diet improves your symptoms, you can begin working with a functional medicine health coach or practitioner to create a plan that will resolve your sulfur intolerance.
Causes Behind Sulfur Intolerance
There may be several different factors that affect your ability to metabolize sulfur, from both internal and external sources
One possible cause is gut dysbiosis — an imbalance of bacteria and fungi in the microbiome that leads to pathogenic overgrowth, causing systemic inflammation, disruption of the digestive process, and other symptoms. This may arise from environmental and lifestyle factors, like chemical exposure, stress, antibiotic use, and a poor diet [2, 3].
When gut health is inhibited by dysbiosis, your ability to correctly process sulfur may be disrupted, leading to first a build up of and then a sensitivity to anything with high amounts of sulfur.
Too much sulfur can also lead to an imbalance in sulfur-reducing bacteria (SRB), which converts the sulfur you consume into a gas called hydrogen sulfide. In normal amounts, hydrogen sulfide can be good for you, potentially having heart health benefits like lowering blood pressure and reducing risk of heart disease [4, 5]. But too much hydrogen sulfide can break down the protective mucus barrier along the gut wall, resulting in leaky gut .
Supplements High in Sulfur
Supplements high in sulfur include:
- Alpha-lipoic acid (ALA)
- Glucosamine sulfate
- Methylsulfonylmethane (MSM)
These supplements are recommended for reducing joint pain and inflammation, as well as boosting immunity. However, they can also increase your sulfur levels and lead to or exacerbate sulfur sensitivity .
Hydrogen Sulfide SIBO
Hydrogen sulfide SIBO is a newer type of SIBO, small intestinal bacterial overgrowth [8, 9]. As mentioned earlier, sulfur-reducing bacteria may overproduce hydrogen sulfide in the small intestine, leading to leaky gut and a wide range of symptoms from altered digestion to brain fog to fatigue.
What’s interesting is that while hydrogen sulfide SIBO might be an indication that your sulfur metabolism is dysregulated, the research is out on whether a low-sulfur diet or avoiding foods high in sulfur will actually provide any benefit. So far, there are no studies that suggest a low-sulfur diet will benefit those with hydrogen sulfide SIBO specifically.
But, there may be other factors at play, so it’s still worth it to experiment with a low-sulfur diet for a short period of time to see whether it helps to relieve your symptoms.
Foods High in Sulfur
In short, figuring out whether you have a sulfur intolerance means that you need to reduce your sulfur intake as much as possible. After you lower your sulfur intake for a few days, you can evaluate whether there has been any change in your symptoms.
Foods high in sulfur content include:
- Brussels sprouts
- Allium vegetables such as garlic, leeks, onions, chives, and shallots 
- Greens, including bok choy, collard, spinach, kale, and chard
- Red meat
- Other game meats
- Parmesan cheese
- Brazil nuts
- Sesame seeds
- Pineapple and papaya
- Dried fruits
- Coconut oil
- Drinking water sourced from a well 
This isn’t an exhaustive list, but these are many of the high-sulfur foods you should look out for. Let’s group some of these foods together into broader categories.
Dairy products are generally high in sulfur content, including eggs, cheese, yogurt, and milk. Butter and ghee, however, are acceptable on a low-sulfur diet.
Cruciferous vegetables are known for their high sulfur content, including broccoli, cauliflower, brussels sprouts, cabbage, bok choy, and arugula. Cruciferous vegetables in particular contain a compound called sulforaphane, which is a phytochemical purported to have benefits like immune modulation, reduction of oxidative stress, and support of cellular detoxification . But in cases of sulfur sensitivity, this compound may not be so helpful.
Though meat and many kinds of fish are high in bioavailable protein, they’re also high in sulfur content. However, organ meats like liver are an exception, as are fatty fish like salmon, mackerel, oysters, and sardines.
Here is a list of low sulfur foods:
- Most fresh fruits, including avocados, apples, bananas, cherries, berries, and citrus fruits
- Root vegetables, including carrots, parsnips, beets, and sweet potatoes
- Squash, including acorn, butternut, and zucchini
- Bell peppers
- All seeds, pumpkin, sunflower, etc.
- Macadamia nuts
- Fatty fish, like salmon, anchovies, herring, and mackerel
- Dark meat chicken and turkey
- Organ meats
- All oils except coconut
- Herbal tea
So although a low-sulfur diet eliminates many food choices, there are still a lot of options available to make filling and delicious meals. Remember, you only have to follow this diet for up to seven days to see whether it will have any beneficial effects.
How to Go on a Low-Sulfur Diet
Introducing and evaluating a low-sulfur diet involves three steps.
Step 1: Eliminate
Step one in the low-sulfur diet is the elimination phase. For one week you’ll eliminate sulfur-rich foods from your meals, replacing them with low-sulfur foods and drinking plenty of water. Since this diet eliminates most animal protein and dairy, you may feel hungrier than usual, so it’s okay to eat more often and make sure you’re getting enough rest.
Step 2: Reintroduce
After a week has passed, evaluate your symptoms. Do you feel better after eating only low-sulfur foods for a whole week? Or are your symptoms unchanged? If you do feel better, begin reintroducing high-sulfur foods over the next one to four days. Make sure to eat multiple servings of sulfur-rich foods in a day and note any changes you experience in your symptoms.
If you haven’t noticed any change throughout the elimination or reintroduction periods, sulfur intolerance is likely not the root cause of your issues.
Step 3: Support
If you do notice a difference in your symptoms on a low-sulfur diet, it’s time to consult your healthcare provider to create a therapy plan that will help your body readjust to sulfur over time. This may involve keeping a food journal to identify triggers and track your progress as you reintroduce foods. You may also utilize certain supplements or self-care practices like Epsom salt baths and sauna use, which can help your body detoxify and readjust.
Remember, there may be other factors at play in your diet, like gluten intolerance or sensitivity, so don’t feel like you need to blindly follow a rigid protocol. Experiment and find what works for you.
You can find a full list of foods and meal ideas in our low-sulfur diet guide.
Other Methods to Lower Sulfur Levels
Besides diet, there are a few other ways you can lower sulfur levels. These are some of our top recommendations to our patients.
Probiotics: There are dozens of peer-reviewed studies showing the effectiveness of probiotics for helping to rebalance the gut microbiome and combat imbalances like SIBO and candida overgrowth [13, 14, 15, 16].
We haven’t yet identified which probiotic species are best suited to fighting hydrogen sulfide SIBO, but we do know generally that a multi-species approach to probiotic therapy is more effective than single-species therapy. We recommend probiotic triple therapy, taking one of each of the three types of probiotics: a multi-strain acidophilus bifidobacteria blend, a probiotic yeast called Saccharomyces boulardii and a soil-based probiotic containing bacillus strains.
B vitamins: B vitamins are essential for metabolising the sulfur amino acid homocysteine . The B vitamin family includes B6, B9 (folate), B12, and riboflavin. A comprehensive B vitamin supplement could not only help you process homocysteine but also support heart and bone health [18, 19].
Molybdenum: Molybdenum is a trace mineral that we need to metabolize the sulfur amino acids cysteine and methionine. A true molybdenum deficiency is rare in the United States, but environmental toxins that sequester this mineral in the soil, plus high sulfur levels, may lead to lower levels of molybdenum in the body . There is limited research showing that supplemental molybdenum may reduce sulfur gases and metabolize sulfur amino acids [21, 22].
Magnesium sulfate: Magnesium sulfate, which is found in Epsom salts, can help break down sulfur amino acids. A warm bath or foot bath with Epsom salts can help your body regulate sulfur levels, plus they’re quite relaxing [23, 24].
Is Excess Sulfur Behind Your Digestive Problems?
A buildup of excess sulfur in the body may be behind a number of digestive problems and other symptoms like brain fog and joint pain. A good way to find out if high sulfur is an issue for you is to go on a temporary low-sulfur diet.
If your symptoms improve after following a low-sulfur diet for a week, you can modify your diet and utilize additional therapies under the guidance of a trained integrative practitioner to bring your body back into balance.
For further guidance on your healing journey from sulfur intolerance, set up a consultation with one of our practitioners at the Ruscio Institute for Functional Medicine today.