Does good food make you sick? Oxalates, lectins and more

There is much pressure to eat fashionable foods like spinach smoothies, hummus, olive oil, milk, tomatoes, red wine, soya and wholemeal bread. Are these really good foods for everyone? Are they really good for you? Lots of people are sick because they eat 'bad food', like sugar and hydrogenated oil, but are you sick because of the 'good food' you eat?  


We have known for a long time that what suits one person doesn’t suit another. Some people feel that natural means good, but isn’t deadly nightshade natural? We have to look for foods that are not only good for people in general but good for us as individuals.


Burkitt and Trowell observed that the fibre in the cooked green bananas eaten in Uganda was very healthy for the gut. However, wheat bran is quite different. Whole grains and whole pulses are fashionable, as they contain more fibre and vitamins than refined grains and split lentils. However, the phytate in them binds to minerals, making them unavailable to us. 


Whole grains, whole roots, whole beans and lentils, and nuts and seeds with skins contain lectins. These are concentrated in the bran layer of seeds. They bind to specific sugars in our bodies, sometimes causing malfunction. Some people eat these without a problem, but some can’t.

Many people can eat a peeled potato, but not one in its jacket. They can eat red lentils, but not green, brown or black ones with skins, and they can eat white bread and white rice, but not brown. They can eat macadamia nuts or roast cashews, but not nuts with skins on.

Other people are more sensitive than that, and have to avoid grains, tubers, pulses, nuts and seeds altogether, and live on fish and meat, with leafy vegetables, and celery, fennel, courgette, squash and cucumber. Celery is a good source of fibre suitable for those with difficulty coping with foods that are high in lectins.


It is not a good idea to eat too many chickpeas. They aren’t pulses, like lentils, beans and peas. They are vetches. It is one thing to eat hummus sometimes, if you tolerate it, but some people do not tolerate it at all. In this case, you could make your own hummus, using red lentils instead of chickpeas. Some people think that is nicer.

Glass of wine on fence


Phenols are in many foods seen as healthy, like red wine, blueberries, onions, green tea and olive oil. They suit the majority of the population, but not those who make too little sulphate, or who are poor at transporting it to where it is needed. Magnesium sulphate is also called Epsom salts. If we have Epsom salt baths, our tolerance of phenols may increase.

Slow transport of sulphate

We detoxify phenols and amines by attaching sulphate to them. Spinach, radish and orange slow down the transport of sulphate, so that it takes longer to deal with chemicals. So these are not foods to eat in quantity regularly. One orange may be ok, but a glass of concentrated orange juice may be too much for you.


Fish is good for us, as it provides us with anti-inflammatory fats called omega-three. However, if it is not fresh enough, there is a lot of amine in it, which can cause symptoms in some people. Aged sausages and mature cheese have the same problem. Epsom salt baths also increase our tolerance of amines.


Boron is in the toxicology textbooks, as it causes digestive problems by depleting riboflavin (vitamin B2). We consume it in plant foods, but should be careful not to overdo it. It is concentrated in tomato sauce, juice and soup, chilli and capsicum peppers, soya, peanuts, hazelnuts and apple juice.


Spinach, rhubarb, sesame, tahini, hummus, beans, cocoa and chocolate contain a lot of oxalate, and we have known for years that those with kidney stones should avoid these foods. We have also long known that oxalates bind to minerals, making them unavailable to our bodies. So high consumption of oxalates can lead to a mineral deficiency.

However, now some people without stones are complaining that these foods make them unwell. It is difficult to be sure, as some of these foods can be undesirable for other reasons. For example, spinach reduces transport of sulphate, and hummus contains chickpeas. Chocolate contains an amine called phenylethylamine.

Person holding bowl of spinach

Cassava, mango and cashews

When it is picked, cassava contains cyanide, enough to kill a rat. Traditionally it was soaked for a long time in a stream, and then boiled without a saucepan lid, so that the cyanide could blow away. So don’t prepare it unless you know how. It can be eaten too much when the maize harvest fails, and people are desperate for food.

Mango is a good food, so long as you cut off the end slice where the fruit was removed from the stalk. Cashews are a healthy food, so long as they are cooked before eating. Just roast them for about 10 minutes, at a moderate temperature. If you buy exotic foods, you need to know how to prepare them.


Fructose is a sugar in sugar cane and beet, fruits, fruit juice, honey, high fructose corn syrup and agave. For centuries people ate little fructose, just occasional honey, and fruit in season. Now it is easy to consume large amounts in cakes, biscuits, puddings and sweet drinks.

If you eat more fructose than your body can remove from the gut to the bloodstream, it concentrates in the gut, feeding unwanted bacteria, and causing gut symptoms. This is called fructose malabsorption. Some people diagnosed with irritable bowel syndrome are simply having too much fructose.  There is also a rare condition called fructose intolerance, in which the body cannot process fructose. This can cause profoundly low blood sugar, in which the body screams for food. 


Galactose is a toxic sugar in milk, which however provides the calf with the energy it needs. Mother’s milk also provides galactose for her baby. A few children have galactosaemia, and cannot tolerate normal milk. Most children cope with it, but consuming this sugar throughout life harms the arteries. It is better to obtain our calcium from hard cheese, from which almost all the sugar has been removed. Preferably have mild cheese, to avoid the amines in mature cheese.

We have different genes, and what is healthy for one is not necessarily healthy for another.

One person’s meat is another person’s allergy. Are you making yourself ill with 'good food,' that suits most of the population but not you? 

It is very hard to treat yourself for food intolerance. An experienced professional, who can look at your own individual issues may be able to help you sort all this out. There are many mechanisms for food intolerance, and but any one test won't tell you what you can eat, and what you can’t. If you'd like support with allergies and intolerances, feel free to message me.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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Stockport, Cheshire, SK4 3NP
Written by Margaret Moss, MA UCTD DipION MBANT CBiol MRSB
Stockport, Cheshire, SK4 3NP

Margaret Moss.

Nutrition and Allergy Clinic
11, Mauldeth Close

Margaret is a nutritional therapist and chartered biologist with an international clinic. She has published many articles in medical journals and for the general public. She specialises in those people who have complex illnesses

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