Toxins lurking in healthy plant foods

The mainstay of healthy nutrition for 40 years now has revolved around eating more plant foods and minimising fatty animal foods. Despite all the variations and debates regarding diet and how to be healthy, the one aspect of nutrition that seems to have remained central to all these diverse opinions is that plant foods are good for us, especially fruits, vegetables, grains, nuts, seeds and beans. Rarely are these foods questioned. Rarely does anyone investigate the effects a plant dominant, modern day diet has on the health of the digestive system and the health of the individual. Whilst plant foods do contribute to health, they do not all come out smelling of roses.

The food pyramid clearly shows the obsession that has been created with plant foods. This illustration defines the basis of healthy eating since 1980 in the USA and 1983 in the UK. If you look closely there is no indication regarding the quality of any of the foods, plant or animal and certainly no guidance about how best to utilise these foods or how to prepare them to ensure they provide the best nutrition. It is correct to think of plant foods as being rich in nutrients, this is both fair and true, but that does not mean that these nutrients are there for our benefit. Plants have worked hard at developing intricate systems to be able draw nutrients from the soil and create needed vitamins and phytochemicals to ensure their own health and strength. It would be a poorly evolved plant that did not have any system in place to protect its valuable nutrients and to put off predators who would destroy and eat it for their benefit. We are taught that species live according to survivial of the fittest - in the plant world that means chemical warfare, because in most cases that is all they have got.

There are many chemicals that plants have developed to stop predators, including humans eating them and living off the valuable nutrients contained within. Some of these chemicals bind to the nutrients preventing us absorbing them once they enter our digestive tracts and others are designed on purpose to damage health and cause distress so that a predator won't eat the plant again. There are five categories of plant toxin that provide the large majority of problems; protease inhibitors, phytates, lectins, oxalates and saponins. The more science is beginning to understand these compounds of plant warfare the more they realise that they seem to have synergistic effects and work together in the same plants to have a more significant effect upon predatory animals, including humans. The following table shows the main foods and the effects these plant toxins cause.

Some of the foods that contain these plant toxins are repeat offenders. Soy beans are probably the most toxic with a tick in every box for all five types of toxins. This is why many people struggle with soy as a food source and why it is listed as one of the legally labelled allergens on any food containing a soy derived ingredient. Many of these toxins in soy are deactivated when the bean is properly soaked and fermented over a long period of time as was done traditionally in Asia. Seeds and spinach also appear in more than one category. The repeat offenders are more likely to be the foods that create problems in people when they are eaten on a regular basis, particularly when they are not cooked and eaten raw as baby spinach leaves and seeds often are in the name of healthy eating. Problems ranging from bloatedness and reduced digestibility to kidney stones and leaky gut all result from ingestion of these plant chemicals found naturally in these foods. Add to the mix the lower nutrient values found in large scale, industrially produced plant foods and the potent doses of fertilisers, pesticides and herbicides sprayed all over these foods and it is no wonder why so many people are beginning to express intolerances to the modern foods we eat, many of them plant foods.

Traditional food preparation methods of long term fermentation, soaking, sprouting and cooking foods all played their role in ensuring that tradional foods were healthy and provided outstanding nutrition. With fast paced food production becoming a necessity for profit making business, most grains, beans and legumes today do not get taken through these nutrient promoting, pre-digesting processes that aid the human gut to do what it does best, absorb foods into the blood.

The point of this blog is not to put people off plant foods as they have formed part of healthy diets around the globe for generations. What is needed is a shift back to the old fashioned ways of soaking, sprouting and fermenting toxin rich plant foods, to break down the incompatible components and to increase the availability of vitamins and minerals to benefit human digestion. Proper cooking in many cases helps to reduce the effects these plant toxins can have on the body, so vegetables, grains, beans and legumes should be cooked to improve their digestibility. This is particularly important as we move into the summer and the tendency of the health minded individual is to eat salads that are often laden with foods that contain plant toxins such as tomatoes, pepper (both nightshades), spinach (rich in oxalates and saponins) and seeds (rich in protease inhibitors and phytates). Whilst these types of salads may be cooling and enjoyable in the warm summer months the toxins therein are their most potent when eaten in raw form. The raw food movement has grown up on the back of the understanding that heat and cooking decreases nutrients that do not tolerate higher temperature or exposure to oxygen. Whilst this is true, they have rarely considered the need to increase the bioavailability of the nutrietns bound by chemicals in raw foods. This means the nutrients are in the plants, but we struggle to digest them and absorb such minerals, so it matters little how much is in the raw plant if we can't absorb it.

Traditional cultures would go through some lengthy processes to ensure their plant foods were edible and nutritious. Nuts in native American tradition were soaked for long periods, rinsed, pounded and cooked before being eaten. this would break down the high levels of phytic acid and reduces protease inhibitors. In central America they would make a type of porridge out of beans and leave it to ferment for several days before eating it. Many cultures would ferment their tubers and root crops after making a kind or paste or porridge with it before eating them. Traditional breads in Europe were made mostly from rye as it has the highest level of enzymes to break down phytic acid and also is most effective at raising the bread in sourdough preparations. Native Americans would ferment cooked corn meal for 2 weeks before consumption.

We do not need to eat these often very sour foods in order to be healthy, but we do need to learn how to prepare our plant foods to minimise the toxic load and release the valuable nutrients contained within for our benefit. The following guidelines should help to develop habits that may aid your digestion of plant foods and ultimately your health.

• soak or sprout your grains
• sprouted grain flours or sourdough preparations for bread
• long soaking (24-48 hours), rinse and cook beans thoroughly
• traditionally fermented soy products only - miso, tempeh and natto
• minimise oxalate rich foods or take calcium citrate at meal times to bind the oxalates and prevent absorption
• moderate or avoid nightshade foods (potatoes, tomatoes, peppers, eggplant) especially if sensitive to these foods

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