01.07.2013 Nutrition

You Are What You Digest

Healthy digestion, not just good food, is vital to good health. Peter Dingle PhD shares his research.

It's how effectively we digest our food rather than simply what we eat that really determines our state of health, says nutritional toxicologist Peter Dingle PhD

You are what you eat or, more accurately, you are what you digest, absorb and metabolise. There are an increasing number of diseases, disorders and irregularities that reduce the ability of the body to digest food, which may then affect absorption and, ultimately, metabolism.

For thousands of years, physicians knew that the key to a healthy body and mind was healthy digestion. Hippocrates, the father of modern medicine, wrote on it extensively as has every physician through to modern times. It's only during the past 50 years, with a predominance of the pharmaceutical health model, that we have turned away from healthy foods and digestion as the keys to our health. How things have changed! The word "restaurant" comes from the Latin term "to restore" and was a place of healing - not a drive-thru. As children, if we ever got a cold we were told to have some orange and lemon; now we are told to take a flu shot (that does not work). I still choose the orange and lemon and throw in some zinc and vitamin C.

The problems with our digestive system and intake of nutrients are further complicated by the array of anti-nutrients, social, environmental and even psychological toxins we add to our modern lives. To name just a few, heavy metals, pesticides, plastics, tobacco smoke, caffeine, medication and stress all lead to a lower level of nutrient absorption in the body. Even if you are eating the best possible nutrient-dense food, which is nearly impossible nowadays, you still may not be absorbing the nutrients your body needs for optimal health.

Populations around the world are so different, from minor differences in genetics to big differences in culture and social systems. Even within a small group of people there is so much variation, between the sexes, age, health status, level of activity, education, income and so on. All of these factors play a role in nutrient needs and access to nutrients.

This is further complicated by the way we treat our digestive system like a rubber hose, dumping stuff into it as fast as we can, as much as we can and all the time justifying that we love to eat. We have lost sight of the role of eating and healthy digestion and, as a result, we suffer.

Chronic Illness

Poor digestion has led to an epidemic of chronic illness from arthritis to Alzheimer's and diabetes, cardiovascular disease to cancer (yes, all of these have there roots one way or another in poor nutrition). We are also now seeing a proliferation of diseases associated with a sick digestive system, including: irritable bowel syndrome, gluten intolerance, psoriasis, bad breath, acid reflux, heartburn, acne, constipation, diarrhoea, yeast overgrowth, fatigue, depression, food allergies and mood swings. Digestive disorders have a considerable impact on quality of life, health care resources, personal and even national economies.(1) There are many health conditions that may affect the gut's absorption of nutrients. These include:(2)

Food allergies and intolerances;Irritation and inflammation of the intestine or colon;Surgery on the digestive tract;Hypochlorhydria or achlorhydria (low or no production of hydrochloric acid in the stomach);Low enzyme production;Infections-including bacteria, yeast and parasitic; andPancreatic, gallbladder and liver disorders.

Not Enough

Acid Perhaps the least understood area of digestion, at least from a treatment perspective, is that slight changes in the pH of the stomach occur as a result of imbalances in mineral absorption. Hence, production of hydrochloric acid or changes as a result of bacterial infections, such as Helicobacter pylori (H. pylori), can affect the breakdown of proteins (and the minerals attached to them) in the stomach and consequently lead to absorption difficulties. Approximately 50% of adults in developed countries are infected by the bacteria Helicobacter pylori, which leads to atrophy of the gastric glands and is a likely cause of nutrient malabsorption, especially for vitamin B12 (cobolamin). H. pylori is the bacteria that causes stomach ulcers. Of 138 patients with vitamin B12 deficiency and anaemia, 58% had an infection of H. pylori; eradication of the bacteria successfully eliminated the B12 deficiency and improved the anaemia. Between 10% and 15% of adults over age 60 are affected by B12 deficiency (3,4).

Probably the most widespread health disorder in Western society is the low level of hydrochloric acid in the stomach, not too much acid like the drug companies tell you. A lack of hydrochloric acid and the resulting poor digestion can lead to constipation and encourage the growth of yeasts and pathogenic bacteria within the digestive system. Hydrochloric acid is critical to the breakdown of proteins in the acid, or pyloric, part of the stomach. Hydrochloric acid not only acts to break down proteins in the stomach but is also an important barrier to microorganisms, such as bacteria. Low levels of hydrochloric acid enable the growth of Helicobacter pylori, the major culprit, along with Helicobacter felis, in stomach ulcers and cancers.

If the stomach is not acidic enough, it can have significant consequences for the rest of the gut and its functions. Significantly, a symptom of a lack of hydrochloric acid is heartburn and reflux. When a person complains to his doctor of heartburn, antacids are generally prescribed, which do the exact opposite of what is usually required and compounds the problem.(5) When the food is not digested properly because not enough acid and other gastric juices are present, it sits in the stomach where it is churned, contributing to acid reflux, as the food has no place to go. Substances like protein, fat and caffeine can also delay gastric emptying. For the past 50 years we have spent millions of dollars treating stomachs with low acid as if they had too much acid. People are diagnosed with reflux and heartburn and are prescribed antacids and proton pump inhibitors, which in most cases exacerbate the problem, not to mention causing serious negative side effects. A low acid stomach also will not activate the rest of the digestive organs into actions such as the release of enzymes from the pancreas, compromising digestion even further. A simple method used by physicians for more than a hundred years has been to sip a little apple cider vinegar with water before each meal to make the stomach a little more acidic (not less).

We also are a bit of an evolutionary mismatch in that our digestive system is one of an omnivore tending on the vegetarian side, yet we eat a lot of heavily cooked meals and often too much meat. Digesting meat requires a lot more hydrochloric acid than we have. Carnivores have around 20 times more hydrochloric acid than we do. Generally when we cook meat, it also makes it even harder to digest because we destroy the naturally occurring enzymes and this is made worse especially if we don't chew it well.

Leaky Gut Syndrome

Intestinal infections cause the symptoms of leaky gut syndrome. There is positive reinforcement of leaky gut symptoms as the intestinal wall is infiltrated by pathogens. The toxins of Helicobacter pylori are the most frequent cause of peptic ulcer disease. Bacteria produce an enzyme called urease, which splits urea into ammonia and carbon dioxide while shielding the bacterium from HCL acid. The ammonia damages the protective mucous layer of the stomach. H. pylori also produces catalase, an enzyme that may protect the microbe from the immune system and several adhesion proteins that allow it to attach to gastric cells.(6)

Gut problems can significantly reduce nutrient absorption and appear to lead to immune deficiency symptoms.(7) Some disorders may lead to decreased fat absorption and can result in a deficiency of fat-soluble vitamins A, D, E and K, as well as essential fatty acids, no matter how well or how much an individual eats. This is also exacerbated by people wrongly blaming fats and going on low-fat diets in an attempt to lose weight or be healthy. This is very wrong and also not healthy.

The gut is a dynamic living organ in the body that is in constant contact and communication with its surrounding media. The mucous membrane absorbs and assimilates foods and serves as a barrier to pathogens and other foreign chemicals and particles (antigens). Optimal functioning of the gut relies on good intestinal integrity. When this integrity is compromised, the permeability of the gut may be altered; little gaps appear and gut function erodes. Two major factors that determine the integrity of the gut are health of the gut lining (the mucosa) and a balanced healthy probiotic (mainly bacterial) population.

The gut lining (mucosa) is composed of close-fitting, thin and semi-permeable (epithelial) cells separated by tight junctures. When the intestinal mucosa (cells including enterocytes and colonocytes) is disrupted, permeability may increase, allowing larger particles, bacteria, undigested foods or toxins to cross the barrier into the blood causing an immune reaction and a subsequent food allergy or food intolerance, or both. This increased permeability is often called "leaky gut syndrome."

Unlike most other cells in the body, which get their energy and nutrients from the blood supply, more than 50% of the energy needs of the small intestine and more than 80% of the energy of the large intestine (where most of the bacteria are found) come directly from the food in the gut and the bacteria. The preferred foods of these cells are short-chain fatty acids like butyrate, acetate and propionate, which are derived from the metabolism of indigestible carbohydrates in dietary fibre by beneficial gut bacteria, especially bifidobacteria. The bacteria in the gut literally create the "food" for the gut lining.

Any change in the relative proportions of different bacteria alters the subsequent nutrients available for the digestive tract and its health. If the right food is not available, the cells can literally get sick and starve.

Among infants, possible factors contributing to the disruption of healthy gut bacteria with resulting dysbiosis and an increased risk of developing allergies, including peanut allergy, include:

  • Antibiotics given to the mother or child
  • Caesarean birth
  • Synthetic chemicals, preservatives and antibacterials
  • Poor quality food including wheat and dairy

It is widely known that the use of broad-spectrum antibiotics has negative effects on intestinal integrity and may alter the balance between beneficial and pathogenic bacteria.8 This is especially important in children, for whom antibiotics are prescribed frequently.9 This effect may be experienced not only if the newborn receives antibiotics, but also if the expecting mother receives antibiotics. Gut dysbiosis may remain for more than 12 months after an initial disruption.

Caesarean Births

Caesarean delivery alters the bacterial colonisation of the gut for more than six months. The gastrointestinal tract of a healthy foetus is sterile. During the birth process and rapidly thereafter, microbes from the mother and the surrounding environment colonise in the gastrointestinal tract until a dense, complex microflora develops. (10) A healthy microflora may have a protective effect against the predisposition to asthma and allergies. A number of large studies have shown that caesarean delivery is associated with wheezing and allergic sensitisation (11,12).

In infants who are breast-fed, bifidobacteria constitute about 90% of their intestinal bacteria; however, this number is lower in bottle-fed infants and when infants' diets are changed to cow's milk and solid food.(13) Foods with a high prebiotic (complex carbohydrates that feed the beneficial bacteria) potential such as vegetables, fruit and beans (legumes) will help maintain a healthy gut bacteria population.

Without a healthy gut we cannot digest and absorb the nutrients in our food and we will get sick.

DISCLAIMER: Dr Peter Dingle is a researcher, educator and public health advocate. He has a PhD in the field of environmental toxicology and is not a medical doctor.


Seifert et al. 2008 Cherniske 1996 Kaptan et al. 2000 Stopeck 2000 Davies and Stewart 1987 Tortore and Grabowski 2000 Archer and Glinsmann 1985 Verdu et al. 2005 Johnston et al. 2006 Schultz et al. 2004 Debley 2005 Negele et al. 2004 Schell et al. 2002

Peter Dingle

Dr Peter Dingle (PhD) has spent the past 30 years as a researcher, educator, author and advocate for a common sense approach to health and wellbeing. He has a PhD in the field of environmental toxicology and is not a medical doctor. He is Australia’s leading motivational health speaker and has 14 books in publication.