Link Between Nutrition & Health


According to the Australian Traditional Medicine Society, nutrition is the “science of food, the nutrients in foods and how the body uses those nutrients.”

Functional nutritionists are trained in anatomy and physiology, with a particular focus on ingestion, digestion, absorption, metabolism, transport, storage and excretion.

Far from dividing foods into their components (fats, carbohydrates, proteins, vitamins and minerals), functional nutritionists are able to recognise how the environment, psychological states and behavioural patterns can impact people’s relationships with food. 

Humans have a complicated relationship with food.

We have moved from eating seasonally and hunting/gathering to having an abundance of food all year round.

Yet despite this abundance of food, global rates of malnutrition have never been higher.

A systematic analysis for the Global Burden of Disease was conducted in 2017 and is studied the health effects of dietary risks in 195 countries between 1990 and 2017.

This was a massive undertaking and revealed that more than 11 million deaths were attributed to dietary risk factors with another 255 million people experiencing some form of disability that was directly impacted by diet. The biggest culprits were:

  1. Increased intake of sodium (salt) which contributed to the deaths of 3 million and the disability of 70 million people
  2. Low intake of whole grains which contributed to the deaths of 3 million people and the disability of 82 million
  3. Low intake of fruit and vegetables which contributed to 2 million deaths and the disability of 65 million people. 

This study noted that there were large gaps between recommended optimal daily intakes and actual intakes of nuts and seeds, milk, and whole grains which contrasted sharply with the overconsumption of sugar-sweetened beverages and processed meat.

The current average consumption of sodium at 6gms a day is 86% higher than what is actually recommended with men generally scoring worse than women.

This study also explored the relationships between diet and disease with China having the highest rates of diet-related cancer deaths and diet related cardiovascular disease deaths per 100 000 population.

Mexico had the highest rates of diet-related type 2 diabetes while Japan had the lowest rate of diet-related cardiovascular disease and disability per 100 000 population. 

According to the WHO, the overconsumption of high-risk foods is not the only complication regarding nutrition.

Unsafe foods containing harmful bacteria, viruses, parasites or other contaminants are responsible for more than 200 diseases ranging with symptoms ranging from diarrhoea to cancer.

This affects almost 1 in 10 people in the world, causing 420 000 deaths and more than 33 million disabilities each year.

Apart from the human cost, there is a loss of US$110 billion as a result of lost productivity and increased medical expenses.

Given the global impact of food quality on human health, it is crucial that nations work together to create and ensure safe food standards and that as individuals, we understand the impact of food on our health.

To complicate things even further, there is no shortage of dietary advice with around 100 diets being touted by social media influences, fitness personalities, doctors, researchers and religious figures.

This course is not designed to promote any one particular diet but to enable confident, independent research so individuals may decide the best options for their own health. 


  • Afshin, A., Sur, P., Fay, K., Cornaby, L., Ferrara, G., & Salama, J. et al. (2019). Health effects of dietary risks in 195 countries, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017.The Lancet, 393(10184), 1958-1972. doi: 10.1016/s0140-6736(19)30041-8


Foods can be broken down into a variety of components.

Some are essential for health and functioning.

These include vitamins and minerals.

Vitamins are divided into those which are fat soluble and those which are water soluble.

Fat soluble vitamins include A, D, E and K while water soluble vitamins include vitamin C and the B group vitamins.

There are also a number of phytochemicals which function in a similar manner to vitamins, these include:

  • Flavonols  – The most abundant source of flavonoids in the diet, these include kaempferol, quercetin (potent anti-inflammatory), myricetin, and fisetin. These compounds are found in olive oil, berries, onions, kale, grapes, tomatoes and red wine
  • Flavones – Similar to flavonols, these are found in herbs such as parsley, thyme, mint and chamomile 
  • Flavanols and flavan-3-ols – This group includes catechins, such as epicatechin and epigallocatechin, which are particularly high in green and white tea and are responsible for many of the health benefits associated with tea. 
  • Flavanones – Found in citrus fruits, flavanones including hesperitin are responsible for the bitter taste of citrus peels.
  • Isoflavones – The best-known isoflavones are genistin and daidzin, which are found in soybeans and soy products. It is thought that isoflavones are responsible for the phytoestrogenic efect of soy which bine to estrogenic receptors to exhibit weak estrogenic effects. 
  • Anthocyanidins – Most red, blue, or purple fruits and vegetables get their color from anthocyanidins. Compounds like cyanidin, delphinidin, and peonidin are present in cranberries, strawberries, blueberries, blackberries, grapes, and red wine



Vitamins are not the only important nutrients obtained from food.

Minerals are also needed for optimal growth and health.

These are grouped into macro and micro minerals.

The seven macro minerals include: calcium, phosphorous, magnesium, sodium, potassium, chloride and sulfur.

Other minerals are needed in smaller doses but are no less important and include iron, zinc, iodine, chromium, copper, fluoride, molybdenum, manganese and selenium. 

The following table outlines trace minerals which are needed in smaller quantities but are no less important for health 



The Microbiome 

The human microbiome is the combination of all living micro-organisms (microbiota) that live on or in human tissues and biofluids.

While they may colonise areas including the skin, mammary glands, lungs, conjunctiva and oral cavity they are most prevalent inside the gastrointestinal system.

In fact, there are trillions of bacteria inside the gut, and they outnumber all the other human cells that make up a person.

Of these trillions of bacteria, there are more than 1000 different species including those from the bacteroidetes, firmicutes, actinobacteria, fusobacteria and proteobacteria families. 

Each person has their own microbiome which is completely unique to them and is made of bacteria, archaea, fungi, protists and viruses.

More research is emerging that points to the importance of the microbiome and the role it plays in attaining and maintaining health. 

Many factors affect the microbiome, these include genetics, environment, weight, disease and diet. 

Our first introduction to other microorganisms is usually during birth when passing through the birth canal and then later through the ingestion of breastmilk.

Later on, interactions with foods and environments provide greater exposure to microorganisms that are both healthy and beneficial.

 The microbiome can affect our health in a variety of ways. In an ideal environment, our microbiome would remain diverse and balanced, able to help us break down and absorb nutrients and act as a defense against more dangerous pathogens. 

For example some bacteria are able to “occupy space” thereby preventing the growth of more dangerous bacteria (competitive inhibition).

Other bacteria (probiotics) are known to confer good health by modulating the immune system, reduce symptoms of allergies, improve mental health and decrease systemic inflammation.

Other bacteria are needed to break down potentially harmful substances in the gastrointestinal tract and are also needed to make B vitamins and Vitamin K.

For example, the enzymes needed to form B12 are found in bacteria, not in plants.

The link between the microbiome and the diet is becoming well established.

Having a diet that is high in vegetables and whole grains is particularly important as foods that are high in fibre are broken down by the microbiota and create as a by-product short chain fatty acids which are used as a source of nutrition and have been implicated in the prevention of bowel disorders, gut dysfunction and cancers.

For example, short chain fatty acids have been shown to be beneficial for the treatment of ulcerative colitis, Crohn’s disease and anti-biotic associated diarrhea. 

If our microbiome becomes unbalanced, or dominated by harmful bacteria, it may lead to an increased risk of systemic diseases such as cardiovascular disease or type 2 diabetes which are linked to low grade, chronic, systemic inflammation.

This inflammation can then lead to a myriad of other health issues, including osteoarthritis. 

However, caution and balance must be taken as a diet that is too high in prebiotic foods may also cause an increase in gas production and bloating.

Similarly, when taking probiotic supplements it is wise to have them before food (even though many are now resistant to stomach acid) and to begin with a slow to moderate dose. 

Strains of probiotics that have been well studied for their health benefits include:

  1. Lactobacillus casei  – used for digestive and immune health
  2. Lactobacillus plantarum – produces antibodies that attach harmful bacteria
  3. Lactobacillus rhamnosus (GG) –  shown to reverse intestinal dysbiosis, reduce chronic inflammation and decrease allergic responses. 
  4. Lactobacillus reuteri – naturally acid and bile resistant, promotes oral health, heart and female health
  5. Lactobacillus agillus – used for digestive and immune health
  6. Bifidobacterium animalis ssp. Lactis – used to support digestion and relieve constipation
  7. Bifidobacterium longum – used to protect intestinal walls from harmful bacteria, helps with digestion
  8. Bifidobacterium breve – inhibits yeast overgrowth, supports the immune system and is linked to positive respiratory and skin health
  9. Bifidobacrium infantis – reduce symptoms of irritable bowel syndrome, abdominal pain and bloating
  10. Saccharomyces boulardii – technically a yeast, nor a bacteria, it promotes a health immune system, aids digestive enzymes and has been used to treat acne and relieve diarrhea. 

It is good to note that strains of Lactobacillus are typically found in the small intestine while the Bifidobacterium strains are usually found in the large intestine and colon. 


The Impact of Diets on Health

Food is and always has been at the core of human culture and civilisation.

Human evolution has seen us adapt to eat what was locally and seasonally available.

The sweeping changes in modern manufacturing, shipping and technology has impacted our food industry and our diet in massive ways. 

It is believed that the food industry is responsible for more than:

  1. 25% of all global green house gas emissions (with cattle and palm oil being among the chief culprits)
  2. 70% of freshwater consumption
  3. 35% of land occupation (needed for crops and cattle)
  4. 66% of the total global disease burden

The impact of modern food production on the environment has largely been negative with threats to multiple ecosystems and biodiversity.

In particular, animal products and meat consumption are believed to be the most harmful not just for the environment but also their impact on cardiovascular disease and increased risk of developing some cancers. 

Given the intrinsic link between our health and the health of our environment it is prudent to consider that any dietary changes should be beneficial, not just for our own health but for environmental health as well.

To add to the confusion, there are no less than 100 different diets touted by all kinds of health professionals, researchers and religious figures. 

Diets that may benefit everyone include traditional diets such as the Mediterranean Diet which has a high intake of fresh vegetables, fruits, good quality oil, fresh fish, minimal meat and even allows for moderate intake of alcohol.

Similarly, a traditional Japanese diet, high in good quality fish, vegetables and soy products has been associated with decreased cardiovascular disease and healthy ageing.

Both of these diets shun the empty calories of refined sugars, fats and high salt and are environmentally more sustainable than the prevalent Western diet.

Both diets have been shown to beneficially impact the gut microbiome.

An example of how damaging this diet is can be seen in Australia where rates of chronic inflammatory and metabolic disease are now three times higher in Aboriginal and Torres Strait Islander populations than in their non-indigenous counterparts.

This may be the result of sweeping changes to the host microbiome as a result of dietary changes. 

With global rates of obesity also rising, portion sizes and how we eat are also factors to consider.

The practice of mindfulness when eating is not a new concept.

Many religions practice gratitude before eating as a mark of respect. Mindful eating is seen as a behavioural change that aims to purposefully pay attention to actions conducted in the present moment without judgement.

Coined by Jon Kabat-Zinn, the art of mindfulness has been proven to improve insomnia, anxiety, depression and the management of chronic pain.

When using a mindful approach to eating, there is an increased awareness of food through the senses – taste, visual appeal and aroma which will correspond to a heightened culinary experience.

The intension is that individuals will be able to better savour food and be aware of when they are satiated.

This approach retrains aims to retrain behaviour with a greater focus of internal awareness.

Unlike other diets, there is no focus on food groups to avoid, rather the focus is on the process of the individual gaining a discerning awareness. 

The best advice is to:

  1. Understand the needs of the body (vitamins, minerals, proteins, carbohydrates, fats)
  2. Understand your body – respect its needs and limitations
  3. Eat fresh and seasonally available 
  4. Avoid fad diets and crash dieting which all lead to longer term damage 
  5. Be present when eating, look at the food, smell the food, slowly taste and savour the food while chewing slowly before swallowing


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  1. Mobegi, F. M., Leong, L. E. X., Thompson, F., Taylor, S. M., Harriss, L. R., Choo, J. M., Taylor, S. L., Wesselingh, S. L., McDermott, R., Ivey, K. L., & Rogers, G. B. (2020). Intestinal microbiology shapes population health impacts of diet and lifestyle risk exposures in Torres Strait Islander communities. eLife, 9, e58407. 
  1. Marco Springmann, Keith Wiebe, Daniel Mason-D’Croz, Timothy B Sulser, Mike Rayner, Peter Scarborough,

Health and nutritional aspects of sustainable diet strategies and their association with environmental impacts: a global modelling analysis with country-level detail,

The Lancet Planetary Health, Volume 2, Issue 10, 2018, Pages e451-e461, ISSN 2542-5196,

  1. De FilippisF, Pellegrini N, Vannini L, et al

High-level adherence to a Mediterranean diet beneficially impacts the gut microbiota and associated metabolome


  1. Jingjing Yin, Degang Yang, Xinhuan Zhang, Yufang Zhang, Tianyi Cai, Yun Hao, Shenghui Cui, Yaning Chen,

Diet shift: Considering environment, health and food culture,

Science of The Total Environment,

Volume 719, 2020, ISSN 0048-9697,

  1. Nelson J. B. (2017). Mindful Eating: The Art of Presence While You Eat. Diabetes spectrum : a publication of the American Diabetes Association30(3), 171–174.
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