Low Phenols Diet by Sue Kira

by sue

Low Phenols Diet

by Sue Kira, Naturopath & Clinical Nutritionist

What are phenols?

About the low phenol diet

Why do some people have an increased sensitivity to phenols?

Signs and Symptoms of Phenol Sensitivities

How to treat phenol sensitivity

Suitable foods for a low phenol diet

What Are Phenols?

Phenols are chemicals that can naturally occur in foods or can be man-made from petroleum products and used as additives in food and personal care items. They are used commercially as preservatives and flavour enhancers.

There are different types of phenols that can cause problems for anyone who has gut issues like ‘leaky gut syndrome’ and especially for children who are naturally more sensitive to chemicals due to their less developed nerve myelin sheaths (the protective coating to our nerves – like the plastic coating around wires).

Phenols include salicylatesglutamates and amines (includes histamines). Click onto the links for further information about these diets.

Many phenol substances are hidden in our foods and not always clearly labelled on the packet or in some cases not labelled at all. Some can be misleading and be called ‘natural’, purely because these chemicals do naturally come from food (but the compound could be concentrated).

Then there’s the fact that some packets of cereals have the boxes sprayed with phenolic preservatives such as BHA (butylated hydroxyanisole). These substances don’t have to be listed but are often in contact with the food.

About the low phenol diet

Phenols naturally occur in most foods to some degree, but there are certain foods that have higher amounts which can be avoided to keep overall phenol levels down. As mentioned, there are three types of phenols found in foods and these are the glutamates, salicylates and amines.


Glutamates naturally occur in foods that have been fermented, including things like soy sauce and sauerkraut, but are also found in bone broths, stock, gelatine, and aged foods.


Salicylates are generally only found in plant matter. Examples include apples, honey, strawberries, grapes, most herbs and spices, tomatoes, and tomato products (tomato sauce, tomato paste etc).


Amines are found in aging meat, dairy and plant foods and are formed by the natural breakdown or decomposition of food. Histamines, one type of amine (note the suffix ‘amine’), includes foods such as chocolate, bananas, strawberries and fermented or smoked foods like bacon, ham, salami, sauerkraut, and yoghurt.

Phenols can also be a by-product of yeast overgrowth (candida, aspergillus etc) or microbial imbalances in the gut, and produced in the body rather than from the consumption of a food.

Why do some people have an increased sensitivity to phenols?

Have you ever wondered why some people can tolerate pretty much any food they eat, while others seem to be quite sensitive to many different foods?

The answer lies in our individual ability to break down these natural chemicals. Our body uses a particular enzyme called phenol-sulpho-transferase, also known as PST, along with sulphate to break down and clear these chemicals from the body without any adverse effects.

Many people have a PST and sulphate deficiency. This is also common for autistic children. These deficiencies can be the result of a combination of factors including genetics, leaky gut, and bacterial imbalances in the gut and mitochondrial dysfunction (a dysfunction in the cell’s energy-producing organelles).

Genetic impairments including methylation and trans-sulfuration impairments are common for those with phenol sensitivity. There is a specific ‘liver detoxification profile test’ that shows a breakdown of the different pathways and how well they are functioning.

Ask your practitioner about this test if you would like to understand more about how these pathways are working for you or your family members. It is a urine test so it’s relatively non-invasive.

When these pathways do not work properly, the ability to digest (from low hydrochloric acid) and detoxify is impaired. Another helpful test to understand what is going on is the test for ‘leaky gut’, as leaky gut can both create and exacerbate phenol sensitivity.

It is interesting to note here that sulphur foods that can help support the sulphation pathway (onions, garlic, broccoli, eggs etc) will often be converted to sulphide (sulphate to sulphide) by the interaction of non-beneficial or overgrowth of bacteria in the small intestine. You will then experience symptoms of irritation from these foods by way of hydrogen sulphide gas (rotten egg gas).

In this case you will need to address any SIBO (small intestine bacterial overgrowth). A low phenols diet will be helpful during this process. Do talk with your practitioner if you suspect this happening. SIBO can be tested via breath or stool sample. Click for more about the SIBO Diet.

Signs and Symptoms of Phenol Sensitivities

As there are many symptoms and signs of phenol sensitivities, the best way to see which ones affect you is to keep a food and symptom diary. Symptoms can be noticed from 20 minutes to two hours after eating the phenol containing food. These may include:

  • Aggression
  • Cravings for high-phenol foods
  • Dark circles under eyes
  • Defiant behaviour
  • Diarrhea
  • Difficulty falling asleep at night
  • Fatigue
  • Headaches
  • Hyperactivity
  • Impatience
  • Inappropriate laughter
  • Incontinence or bed wetting
  • Poor neuromuscular function
  • Red cheeks and/or ears
  • Respiratory issues
  • Self-injurious behaviour/head banging
  • Skin rashes
  • Sleep walking

Some of these symptoms can be related to other disorders but phenol sensitivity may still be a possible contributing factor to these symptoms, so it is certainly worth trying the low phenol diet.

How to treat phenol sensitivity

  • The first thing to do is to try the low phenol diet which excludes amines, salicylates and glutamates. Keep a diary to track foods, symptoms, bowel movements and sleep. Note any changes in symptoms, both good and bad. Give each a score between 1-10, so you can see any subtle changes as you go. This will help you to build a picture of foods that are suitable for you and those to avoid.
  • Talk to your practitioner about using certain supplements such as specific enzymes that help to break down phenols. Because most foods contain some level of phenols, you won’t be able to exclude all of them, but reducing them as much as possible and using the enzymes that help to break them down all helps.
  • If tolerated, you can increase sulphur rich foods in your diet to help with this pathway. If symptoms get worse, then leave these out for now and talk to your practitioner about checking for SIBO, leaky gut and liver detox pathways and address them as needed. Foods that are naturally high in sulphur and sulphur containing amino acids include, onions, garlic, leeks, shallots, brassica family of vegetables such as broccoli, Brussel sprouts, cabbage, cauliflower, kale plus all meats, poultry and eggs.
  • Another way to increase sulphur without the flatulence is with Epsom salts baths. This way the sulphur (magnesium sulphate) is absorbed via the skin, which is by far the best way to get both the sulphur and the magnesium into the bloodstream. If you don’t have a bath, even a bucket or tub of water and a foot soak can still do the trick. Use a ¼ cup of Epsom salts initially to ensure no detox reaction and then slowly build up to 2 cups to a warm/hot (how you like it) bath three times a week. If the dose is too high you might feel ill, so start slowly.
  • You may wish to also look at methylation defects. This can be checked via genetic testing with your doctor or naturopath. You can either test the whole lot (all genes that can be tested to date) or just those related to methylation. The key ones to check are MTHFR (two main genes) which look at how well you can convert folate. There is much information on this topic and the diet to support this is the Diet for MTHFR/Methylation. Addressing any MTHFR methylation pathways helps to support other pathways.

Suitable foods for a low phenol diet

The way the Low Phenol Diet works is that you choose foods from specific low phenol food groups (see below). You would normally follow this diet plan for one to three months, depending on your symptoms and practitioner’s advice.

Because the low phenols diet restricts salicylates, glutamates and amines, the  available food options are quite limited. As a result of being on a restricted diet, you run the risk of being deficient in certain nutrients, which is why it’s super important to work with a practitioner who can support you with extra nutrients as needed.

At the appropriate time, your practitioner will guide you by gradually reintroducing foods from each of the phenol groups i.e. salicylates, glutamates and amines.

Along the way you may find the reactions are stronger in one phenol group over another. For example, only the salicylates foods could be an issue, in which case the foods with glutamates and amines could be well tolerated and re-introduced back into the diet.

Be aware that the following lists are not going to cover all foods available, just the most common ones. There may also be some foods on this list that you may react to for other reasons than phenols, so be guided by your health practitioner’s advice and most importantly, how you feel.

This diet should also exclude all food additives, both natural and chemical to avoid additional sources of phenols. The following lists have the low and medium phenol foods that are included in this diet.

To make it easier, I have not included high phenol foods, but these can be found in the appropriate articles for the specific phenol. See amines (includes histamines), glutamates and salicylates.

Vegetables low in all phenols

  • Potato, ‘old’ type, brushed white, must be peeled (not new or baby potatoes)
  • Lettuce, Iceberg (highly sensitive people discard outer dark green leaves)
  • Bamboo shoots, tinned or fresh (drain and rinse well)
  • Bean shoots, very fresh as they develop amines by fermentation
  • Celery
  • Choko (Chayote pear)
  • Swede

The above group are the super low reactive for most people. Below are low phenol foods, however some people may react to these in different ways such as gas, bloating, changes in bowel habits due to SIBO, bacterial imbalances, or if reactive to FODMAPs (fermentable carbs).

  • Brussel sprouts, fresh or frozen
  • Cabbage, red, green (drumhead), savoy, wombok (Chinese cabbage)
  • Chives, Shallot/spring onions & leeks
  • Garlic, in very small amounts only

Vegetables with medium level phenols – have minimal of these

(Mostly salicylates in this group. Peas have some glutamate).

  • Asparagus
  • Beetroot
  • Bok choy, pak choy
  • Carrot, both raw and cooked
  • Cucumber, fresh and peeled
  • Kumara/Sweet potato
  • Lettuce, all types (iceberg is low)
  • Marrow
  • Parsnip
  • Peas, green peas only
  • Peas, snow peas, sugarsnap peas
  • Potato, blue, yellow, new, pink, purple, red
  • Pumpkin, butternut, squash
  • Turnip
  • Zucchini, peeled

Fruit low in phenols

  • Pears fresh and peeled
  • Pears, canned in syrup (not juice)

Fruits with medium level phenols – have minimal of these

  • Apples ripe/peeled – Golden Delicious, Red Delicious (other types high)
  • Loquat
  • Pear peeled, unripe
  • Pear canned in juice, drained
  • Pear juice home-made
  • Nashi pear peeled, ripe
  • Banana just ripe (salicylates in unripe and amines in over ripe)

Other low phenol foods

  • Fresh meat, fish, and chicken (fresh or frozen) and egg yolks (whites have high histamines). Avoid any meats processed, seasoned, aged, smoked
  • Grains – rice, buckwheat, quinoa (rice the safest)
  • Milk substitutes – coconut milk (some can be sensitive) and rice milk
  • Canola oil, safflower oil, lard, duck fat, chicken fat, rice bran oil
  • Salt and white pepper
  • Fresh Coriander, fennel (small amounts), saffron, horseradish (not pickled)


Before you commence your diet, see your medical or health care professional for qualified guidance about what foods and supplements are best for your body. While on the diet do not stop any medications or supplements previously prescribed unless advised otherwise by your medical or health care professional.

During the early stages of a new diet, you may experience symptoms such as fatigue, headaches, or body aches, which may occur because your body is detoxifying. However, if you are unsure about a symptom at any time, check immediately with your medical or health care professional.


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