Enzymes – the mystifying nutrients


Based on the pioneering work on the subject by Dr Edward Howell, published in his book, Food Enzymes for Health and Longevity, this article has been abstracted, modified and added to by Editor, Roger French.

 Summer 2015/16 True Natural Health Magazine

Sweeping the natural health world is a growing awareness of the crucial role in health and longevity of a large group of nutrients, the roles of which are somewhat obscure.

These nutrients – the enzymes – may well be the most important casualties in the cooking of food, the harm of which has been warned about for a century by natural therapists urging the use of raw foods.

Enzymes are not a recent discovery. Dr Edward Howell assessed their value 80 years ago, but only in recent years has the word, ‘enzymes’, become a household word.

Enzymes are a double-edged sword. While being critical to our wellbeing and to life itself, they are also the agents of food perishability and therefore the cause of great inconvenience to the food industry and to consumers alike. Understanding their usefulness and how to avoid their negatives can be very helpful.


In the same way that chemical reactions in the school laboratory can be triggered off by catalysts, the chemical changes that constitute all the life processes in all living things require catalysts to trigger them off. Enzymes are simply biological catalysts.

As with vitamins and minerals, enzymes occur in all vegetable and animal tissue in its natural state, so that all wild animals always ingest them with their food.

Enzymes make possible the energy supply for every one of the millions of processes occurring within the human body. They are necessary for the digestion of food, for the metabolism of food after digestion, for the elimination of wastes and for all other bodily functions.

Each enzyme has a specific purpose so that there are tens of thousands working away in the human body, with something like 50 thousand in the liver alone.


Surprisingly, the less food that is consumed on a long-term basis by insects, animals and humans – but above starvation level – the longer they live. In the case of insects and animals, by restricting the quantity of food, it is even possible to double the life-span. Increasing the temperature causes insets to be vastly more active – like mosquitoes in summer – but they die sooner. It appears that more food or greater activity causes more enzymes to be used up and this reduces longevity.

In humans, enzyme levels are highest in young adults and decline with age. One of the digestive enzymes was found to decrease in quantity by about 30 times by the age of 80. It has been found that bigger college students tend to have poorer health than those who have grown less rapidly (and used-up their enzymes less rapidly.)

It appears that maximum growth rate and longevity are incompatible. In addition, because greater enzyme potential is associated with increased vitality, enzymes may well emerge as the true yardstick of vitality. Put another way, the enzyme potential and the life-force may be the same thing.


A very important question is whether enzymes consumed in food can work in the body. If they can, then the enzymes manufactured in the body will be conserved and the enzyme potential increased, leading to better health and longevity. Generally, it has been assumed that food enzymes cannot work in the body, but Dr Howell has produced evidence to the contrary.

Very interesting experiments found that it is possible for complex substances, such as bacteria, yeast cells, proteins and fats which were not digested, to be absorbed into the blood stream, where they provoked an allergic response. It was found that if there were adequate enzymes in the blood, the enzymes would complete the digestion of the substances, but if the levels were low, symptoms of allergy occurred. When enzymes were administered orally to the patient the symptoms subsided, demonstrating that external enzymes could work in the body.

Food enzymes commence the digestion of a food the moment the cell walls are ruptured by chewing. Later on the body’s own digestive enzymes begin to work and some of them are very powerful. Pepsin breaks down the protein in eggwhite in just a few minutes, but it takes hours to do the same thing in a laboratory.

Because cooked food can be digested with apparent ease by most people, it is usually assumed that food enzymes are destroyed in the acid medium of the stomach. But this is wrong.

It has been shown over and over again that, although some are destroyed in the stomach, the enzymes in raw food play an important part not only in assisting the digestive processes and thus relieving the pancreas of extra work, but also in supplementing the other enzyme production within the body.

Some animals, notably ruminants, have a separate stomach – a ‘food enzyme stomach’ – in which food is pre-digested by food enzymes before the body’s digestive enzymes are called upon. The human stomach functions as two parts, the upper part performing the same function as the food enzyme stomach in animals.

There is no doubt that food enzymes play a significant nutritional role in contributing to our total enzyme potential.


Increased metabolic activity is paralleled by a rise in the enzyme content of the blood and occurs during muscular work, increased food intake, pregnancy and fevers.

Enzymes activity requires the presence of moisture and varies with temperature and acidity, according to the particular enzyme. In the human body, enzyme activity reaches a maximum at fever temperatures in order to achieve the maximum rate of action by the body’s defences. For every one degree centigrade rise in temperature, the basal metabolism increases by approximately 13 percent. Because bacterial activity decreases in fever, it is thought that increased enzyme activity is the main mechanism in the body’s defence against bacteria. The body’s defending cells, white blood cells, possess a greater diversity of enzymes than any other kind of cell and are thus able to digest bacteria.

In contrast to the situation in acute illness, enzyme levels are always low in chronic disease. If the enzyme content becomes so low that metabolism cannot proceed, death occurs.

Enzymes have another interesting role in disease, this time in prevention. Raw food enzymes reaching the colon (bowel) regulate the natural intestinal bacteria (the microflora) by binding any oxygen present. This eliminates the aerobic condition in which harmful bacteria grow and cause fermentation and putrefaction leading to toxaemia and consequent degenerative diseases including cancer. With the harmful bacteria gone, the beneficial bacteria can flourish and carry out their vital work, including the digestion of plant cell walls and the manufacture of vitamins, particularly some B vitamins.


Enzyme activity increases with temperature, but only up to a surprisingly low temperature, at which it tapers off, namely 42ºC. If the enzymes in raw food are heated to 48 ºC (118 ºF) for more than half an hour they are completely destroyed. However, dry heat – which does not occur in foods – is not destructive to enzymes until above 150 ºC (302 ºF).

Thus the natural, health-giving enzymes found in all raw foods are totally destroyed by cooking and even by pasteurisation – to our peril.


Wild jungle animals live exclusively on raw food and don’t develop degenerative disease, but when fed cooked food in captivity disease becomes rife. When a raw food diet is restored, their health improves again.

The differences in health, physical condition and lifespan between animals maintained on a cooked, vitamin-supplemented diet, and animals maintained on a raw food diet can only be attributed to the extremely heat-sensitive enzymes in raw food.

The significance of enzymes in raw milk is supported (not proved) by an early Chicago study of 20,000 babies, in which seven percent of those that died were breastfed, compared to 66 percent of deaths in the bottle-fed group on pasteurised milk.

Although Bulgarian peasants ate large quantities of dairy products, including sour milk, they achieved unusual longevity. All the dairy products were raw and unpasteurised.

Our appallingly high incidences of cancer, heart disease, diabetes, arthritis and other degenerative diseases is consistent with the expected results of enzymes damaged in a highly cooked diet. Conversely, the therapeutic value of a diet of raw fruits and vegetables and/or their juices, which has been established repeatedly all over the world, is exactly what we would expect.

The ‘life force’ that we attribute to raw foods may well be largely due to their enzyme content.


 In humans eating cooked food, the gland that produces most of the digestive enzymes, the pancreas, is enlarged due to overwork. In proportion to total body weight, it is over twice the size of that of herbivorous animals, the only explanation being the cooking of food.

Consistent with this, Oriental people on a high-carbohydrate cooked diet, mainly rice, have a pancreas approximately 50 percent larger than that of Western people. The salivary glands, which produce the starch-digesting enzyme, ptyalin, are also larger. Interestingly, cattle and sheep, on raw high-carbohydrate diets have inactive salivary glands and only very small pancreases. They are obviously dependant on food enzymes for digestion.


Although we would naturally expect raw vegetable to be high in enzymes, they are not. The enzymes content of raw natural foods is roughly proportional to the calorie content, and bulky vegetables are very low in calories.  Therefore, the addition of salad to a meal of cooked meat and potatoes will not compensate for the enzyme destruction.

Fresh fruits are high in enzymes, which are responsible for rapid ripening and then the fruit going bad, more rapidly in hot weather. Bananas are a striking example of this. By comparison, vegetable only wilt and shrivel.

Animal foods – meat, fat, eggs and dairy products – when raw and unpasteurised contain valuable enzymes (of course, this is not a recommendation for meat in the diet).


The seeds of all plants contain abundant enzymes, but these are inhibited by ‘enzyme inhibitors’ until temperature and moisture are right for germination. This is why seeds may last for years in the soil without rotting.

Unfortunately, enzyme inhibitors are also effective against digestive enzymes, which means that, as a general rule, seeds are difficult to digest.

Soya beans and peanuts are particularly high in enzymes inhibitors and need to be cooked or preferably sprouted to destroy the inhibitors.

Cereal grains, the ‘starchy’ foods, must be cooked for us to be able to digest them. Firstly, heat is needed to burst the fibrous wall surrounding the starch and, secondly, the enzyme inhibitors must be destroyed to enable its digestion. Of course, the valuable food enzymes are also destroyed. Consequently, cereals, although considered the staff of life, are not ideal foods for humans unless sprouted.

Nuts, being the seeds of trees, contain enzymes inhibitors which cause many people to notice discomfort with more than small quantities of nuts at a meal. It is best to soak nuts to initiate germination and consume them raw.


Cooked food keeps well because its enzymes have been destroyed. Otherwise it would decompose as quickly as fresh food.

Because enzymes are inhibited by cold, refrigerated food keeps well, and frozen food will keep indefinitely.

Similarly, because enzymes need moisture, dehydrated food will keep indefinitely.

Canned foods keep indefinitely because the enzymes have been destroyed by heat (pasteurisation as least) and the food sealed in the canned against bacteria which could reintroduce enzymes.

Preservatives work by inhibiting enzymes, and therefore they must be difficult to digest.


Enzymes are of crucial importance to the processes that constitute life.

They are biological catalysts which trigger off every single life process.

All animals in the wild consume abundant enzymes in their diet.

Cooked and pasteurisation destroy all enzymes.

In humans eating cooked food, enzyme-producing glands enlarge and are over-worked in compensating for the deficiency in the diet.

All seeds contain enzyme inhibitors to preserve them. They are made less indigestible by cooking and completely digestible by sprouting.

Food preservation depends upon the destruction of food enzymes.

Enzymes are so fundamental to life that our lifespan depends on the supply of them. A diet of uncooked foods greatly increases this supply – and our lifespan.



Food Enzymes for Health & Longevity by Dr Edward Howell

The Health Revolution 3rd Edition by Ross Horne