What's the big deal about calcium?

Almost all of the calcium in the body (~99%) is found in the bones (and teeth), where it is essential for building and maintaining bone to give the bone its strength. The remaining ~1% is dissolved in the bloodstream and other fluids where it is used for maintaining the function of the heart, muscles, blood and nerves. We continuously lose calcium each day through our skin, nails, sweat and urine.

What happens if your diet is low in calcium?

Our bodies cannot make calcium, therefore all our calcium requirements are provided by our diet. If our diets do not provide sufficient calcium, there will not be enough calcium available in the bloodstream for our bodies to function properly. This means some of the calcium crystals stored in the bone will dissolve to 'stock up' the calcium needed in the bloodstream. If your calcium intake remains too low, the calcium in your bone will continuously need to dissolve and be released into your bloodstream, and you risk losing bone strength.

Calcium absorption

As well as increasing your intake of calcium, it is also essential that the calcium is able to be absorbed by the body. Calcium absorption can be reduced by excessive alcohol or caffeine consumption, as well as consuming a diet high in animal proteins or drinking soft drinks that contain phosphates. As we age, calcium is absorbed less effectively from the intestine thus we need to increase our intake of calcium to avoid losing bone density which may result in osteoporosis.

The greatest rate of bone growth is reached by puberty, and by age 30 we reach our peak bone mass (maximum bone density). The higher our peak bone mass, the better our bone health will be in the future. This is particularly important for women as rapid bone loss occurs during the menopause. As puberty is an essential time for determining your overall bone health, it is critical that children and teenagers get enough calcium.

Your daily calcium requirements depend on your age and sex. Less than half of Australian adults get their daily recommended intake of calcium.

Sources of calcium

Dairy

Dairy foods such as milk, yoghurt and most cheeses are calcium-rich and serve as the primary source of calcium in our diet. Calcium is also more easily absorbed from dairy products compared to other food groups.

Aim to eat 2-3 serves a day such as a glass of milk, a slice of hard cheese or a yoghurt.

Photo by adam morse on Unsplash

Canned fish

It's not only humans that have high levels of calcium in their bones. Consuming canned fish including the bones will also help you increase your calcium intake.

Try canned salmon or sardines!

Eat more fruit and veg!

Small amounts of calcium are also found in fruit and vegetables, particularly greens such as broccoli and kale. Nuts are also a great way to introduce more sources of calcium into your diet, particularly almonds.

Useful resources

Australian dietary guidelines 2013

https://www.eatforhealth.gov.au/sites/default/files/files/the_guidelines/n55a_australian_dietary_guidelines_summary_book.pdf

Nutrient reference values for New Zealand and Australia

https://www.nrv.gov.au/nutrients/calcium

Arthritis WA

https://www.arthritiswa.org.au/content/page/osteoporosis-prevention.html

Calcium content of various foods

https://www.arthritiswa.org.au/useruploads/files/calcium_content_table.pdf

NHMRC Food for Health

https://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n31.pdf

Bowel cancer

Bowel (or colorectal) cancer is the second most common cancer in Australians and is particularly prevalent in those over 50 years of age. Symptoms of bowel cancer include a change in bowel habits, thin bowel movements, blood in the stools, abdominal or rectal pain, fatigue or weight loss. It is estimated that 16,682 new cases of bowel cancer will be diagnosed in Australia in 2017, accounting for 12.4% of all newly diagnosed cancer cases in Australia.

Incorrectly, many people believe that bowel cancer primarily affects men. However, it is also the second most common cancer amongst women, second only to breast cancer. A survey of 787 people by the Cancer Institute NSW found that whilst 69% of respondents recognised that bowel cancer commonly affects men, only 37% knew of its prevalence among women.

Bowel cancer develops from the inner lining of the bowel and is usually preceded by growths on the inner lining of the bowel that often protrude into the intestinal lumen. These growths are known as polyps and are caused by genetic changes or mutations. Although fairly common, polyps can become malignant (cancerous) and need to be monitored in order to recognise the signs that cancer may be developing.

There are various other factors that increase your risk of developing bowel cancer including a genetic vulnerability, inflammatory bowel disease (such as Crohn's disease or ulcerative colitis), being overweight or obese and environmental factors including high alcohol consumption, high red meat consumption (particularly processed meat) and smoking. By eating a healthy diet with plenty of fresh fruit and vegetables, maintaining a healthy body weight and not smoking the risk of developing bowel cancer can be reduced.

According to the Australian Institute of Health and Welfare, not only is bowel cancer the second most common form of cancer, it is also the second biggest killer after lung cancer. It is estimated that there will be 4,114 bowel cancer deaths in 2017, up from 4,071 deaths in 2014. Currently the five-year survival rate for Australians diagnosed with bowel cancer is 69%. Bowel cancer can be treated when diagnosed early, and the National Bowel Cancer Screening Program currently provides free screening kits that can be done at home for people over the age of 50. However, despite its importance, only 34.5% of those eligible for screening in NSW actually have completed these tests.

One of the biggest problems is the issue of stigma, with bowel cancer being seen as 'dirty or embarrassing', a view which is decreasing the rate of screening uptake. Although most people realise that early detection and diagnosis is essential in treating diseases such as bowel cancer, many are embarrassed to seek information and advice, or report concerns to their doctor. This embarrassment and stigma is costing lives and needs to be tackled to make people aware of the importance of screening to minimise their risk of bowel cancer.

Sources

The statistics presented above are summarised here and originally sourced from the Australian Institute of Health and Welfare.

Should I be eating more prebiotics?

What are prebiotics?

A prebiotic is a type of non-digestible fibre that promotes the growth of beneficial organisms in the intestine. As prebiotics aren't digested in the stomach or small intestine, they reach the colon (large intestine) and are fermented by the bacteria in the gut to be used as an energy source. In other words, prebiotics are the food or energy source for the healthy bacteria found in our gut.

In order to be classified as a prebiotic, it must:

• Pass through the gastrointestinal (GI) tract undigested,
• Act as food and stimulate the growth and/or activity of certain 'good bacteria' in the colon,
• Induce effects that are beneficial to the health of the host by making the gut environment healthier.

Sources of prebiotics

Chances are you're already eating some prebiotics in your normal diet. Good sources of prebiotics are listed in Table 1. As a general rule, to get the most out of the prebiotics found in vegetables, they should be eaten raw, for example in salads, smoothies or hummus, or otherwise gently cooked such as by steaming. In addition to being good sources of prebiotics, many of these foods are also excellent sources of dietary fibre which is recommended for a well-balanced diet.

Table 1: Food sources of prebiotics

Vegetables	Chicory root, Jerusalem artichokes, garlic, onions, leeks, asparagus, dandelion greens
Legumes	Chickpeas, lentils, red kidney beans, baked beans, soybeans
Fruit	Unripe bananas
Wholegrains	Barley, rice, quinoa, oats

Health benefits

Prebiotics are a relatively new topic of discussion, and are far less well-known than 'probiotics' – cultures of live microorganisms, often termed 'good bacteria', that confer a health benefit by rebalancing the balance of bacteria in the gut. The evidence backing the health benefits of prebiotics is still limited and requires further investigation, although it is suggested that prebiotic intake may:

• Reduce the prevalence and duration of diarrhoea associated with infections or antibiotics.
• Reduce symptoms associated with inflammatory bowel disease.
• Exert protective effects to prevent colon cancer.
• Reduce episodes of constipation.
• Enhance the uptake of minerals including calcium which may maintain bone density and reduce the risk of developing osteoporosis.
• Lower some risk factors for cardiovascular disease.
• Promote satiety (feeling full after a meal) and weight loss to prevent obesity.

Irritable bowel syndrome

Although the health benefits of prebiotics sound great, they're not for everyone. Patients with irritable bowel syndrome (IBS) for example are advised to follow a low FODMAP diet. FODMAPs are indigestible sugars that act as 'fast food' for gut bacteria. In IBS, FODMAP foods are poorly absorbed in the small intestine and are instead fermented by bacteria in the colon, producing gas and contributing to the symptoms of IBS. Unfortunately many of the foods that are good sources of prebiotics are also high-FODMAP foods and are not advised for IBS sufferers, so if you are considering a noticeable change to your diet it is important to discuss your options with your doctor or dietician.

Should we all be taking probiotics?

Over recent years there has been a surge in products containing live cultures of 'good bacteria', or 'probiotics', that claim to aid digestion, ease intestinal problems and keep your gut microbiota (the microbial population that lives in your gut) balanced and healthy. But are these probiotics as good for you as they seem?

In fact, there is actually little evidence to support the claim that the 'friendly bacteria' contained in probiotic drinks, yoghurts and supplements have any effect on healthy people. A group of Danish researchers from the Novo Nordisk Foundation Centre for Basic Metabolic Research, University of Copenhagen, recently reviewed the results of seven randomised controlled trials of probiotic products and supplements on the faecal microbiota of health adults and found little evidence of change.
Reviewing trial results of various probiotic products including biscuits, milk-based drinks, sachets and capsules, the team investigated their effects on the overall composition of faecal microbiota including the number of species present and the distribution of species with a population, and compared findings with those taking a placebo.

Lead author Professor Oluf Pederson said that although previous studies have shown that some probiotic interventions may help people with diseases that cause imbalances in the gut, there was "no convincing evidence [...] for consistent effect of examined probiotics on faecal microbiota composition in healthy adults" and indicated the need for much larger, carefully designed and conducted clinical trials.

On the other hand, there is some evidence to suggest that probiotic therapy can benefit people with irritable bowel syndrome (IBS). In addition, people taking antibiotics for a prolonged period of time may disrupt the balance of good and bad bacteria in the gut so may be advised to take probiotics during their course, and for several weeks afterwards, in order to replenish their gut microbiota.

Even though taking probiotics may be helpful in these situations, it is advisable to discuss your options with your doctor or dietician, who may take a stool sample to determine which probiotic would be most beneficial for you. This is because what is deemed as a 'healthy microbiota' is not the same for all people, and what may be good for one person may not be so good for another. Therefore, although taking certain probiotics may be helpful to one individual, they could actually be harmful to someone else. It is important to have a healthy balance, but this balance needs to be specific to your individual system.

A recent study by PhD student Amy Wallis and co-author Dr Michelle Ball, both of Victoria University, suggested gender-specific differences related to the gut bacteria in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Using faecal microbial data and self-reports from 274 patients with ME/CFS, Wallis and colleagues found sex-specific interactions between certain bacteria of the phylum Firmicutes and ME/CFS symptoms. For example, high levels of Streptococcus bacteria in the gut related to increased symptoms in men with CFS, yet decreased symptoms in women.

"This and other results with Lactobacillus bacteria show that caution is needed when using probiotics as, in some cases, it could do more harm than good," Wallis added.

Further research is still required to determine the cause of these sex-specific differences, although Wallis suggests that they may be linked to how hormones and the microbiota affect the immune system. In the mean time, these results show the need for caution in probiotic use.

The lack of evidence of a genuine cause and effect relationship has caused Europe to put in place strict regulations which include banning the term 'probiotic' on packaging for products that contain live cultures of 'good bacteria', highlighting the need for further research into whether probiotics do have health benefits. Currently the Food Standards Australia and New Zealand (FSANZ) do still allow the term probiotic to be used on packaging, however they have adopted a new framework for regulation.
An additional issue with 'probiotic' packaging is that many products don't specify how many bacteria they contain, and even if they do, this is only relevant at the time of packaging, as storage, light, air and moisture can all affect the bacteria and there is no way to determine how many are still alive by the time you consume the product. Likewise, specific scientific research is often over-generalised, advertising probiotic bacteria at the species level rather than the specific strain or using made up names that sound 'scientific' yet continue to brand their product.

Although it is true that maintaining a healthy gut microbiota is important for overall health, probiotics may not be the answer. Generally speaking, the best way for healthy adults to improve their gut health is to have a varied, balanced diet that is high in fibre. In addition, prebiotics (non-digestible food ingredients that promote the growth of beneficial microorganisms in the intestines) have been suggested to be a better choice than probiotics as they act as food for the good bacteria already present inside your gut, improving the balance, rather than adding new bacteria to the microbiota. If you must take probiotics, generally probiotic-rich whole foods are recommended over supplements due to the added nutritional benefits such as the high levels of calcium found in yoghurt.

Dietary advice for inflammatory bowel disease

Poor nutritional health and IBD

There is no evidence to support that diet or food allergies can cause, prevent or cure inflammatory bowel disease (IBD) such as Crohn's disease or ulcerative colitis. However, diet is an important consideration for individuals with IBD – especially those with Crohn's disease – as they are more at risk of poor nutritional health due to:

• Loss of appetite due to abdominal pain, nausea, fear of eating and worsening symptoms.
• Poor digestion and malabsorption due to the disease itself or medications.
• An increased need of nutrients for the body – chronic diseases such as Crohn's disease increase the energy needs of the body, particularly during flare ups.

Nutritional deficiencies are common in IBD, particularly Crohn's disease and can cause added complications such as anaemia, weight loss and impaired growth and development (in children). Therefore, in some cases nutritional supplements may be advised.

How IBD will affect my diet

Generally, most people with IBD should eat a varied, well-balanced diet, however it is advised that you consult with your GP or dietician to develop an individual diet plan based on:

• Which disease you have (Crohn's or ulcerative colitis).
• For Crohn's patients: Whether you have an intestinal stricture (narrowed section of the bowel).
• What part of your intestine is affected and to what severity.
• Whether your disease is active or inactive.

For inactive disease it is generally advised that you have a well-balanced, nutritious diet, however during active disease additional considerations may be required.

Although there are plenty of diets advertised for especially managing IBD it is important to remember that the success rate of alleviating symptoms depends on the individual, there is no scientific evidence to support these diets. The best method to find a diet that works for you is to keep a food journal to track what you eat and your body's reaction and discuss this with your GP or dietician to develop a customised diet plan for you.

General dietary considerations for IBD

Certain aspects of your normal diet may not be tolerated well during IBD flare ups and may need altered following a discussion with your doctor/dietician.

Trigger foods

A benefit of a food journal is that you can keep track of which food act as triggers and worsen your symptoms as they will not be the same for all IBD sufferers. You may then be able to eliminate these certain foods from your diet, however it is essential this is done with the supervision of your doctor or dietician to ensure it doesn't result in nutritional deficiencies.

Fibre

For general health a high fibre diet is advised, however for many people with IBD may find that consuming fibre during active disease or if they have strictures may cause abdominal cramps, bloating and worsening diarrhoea. Insoluble fibre (doesn't dissolve in water) in particular is a harder, more coarse fibre that is more difficult to digest and can exacerbate IBD symptoms and even cause intestinal blockages in severe disease or when strictures are present. Soluble fibre (does dissolve in water) on the other hand absorbs water and makes food move more slowly through the intestine and can reduce diarrhoea. Most foods contain a combination of soluble and insoluble fibres.

Cooking, peeling and removing seeds from fruit and vegetables, and avoiding wholegrain carbohydrates are important ways for IBD patients to reduce their intake of insoluble fibre when required.

Lactose

Some people with IBD are also lactose-intolerant which can be diagnosed with a simple test. Some Crohn's disease patients may lack the enzyme 'lactase' found in the small intestine which breaks down lactose and therefore may need to avoid milk and other dairy products. Dairy products are an important source of calcium so supplements may need to be taken to avoid deficiencies.

High-fat foods

People with IBD may struggle with fat absorption and eating high-fat foods such as butter, margarine or cream may lead to increased diarrhoea or gas.

Fluids

It is essential to keep hydrated, and it is recommended that you drink 8-10 glasses of water a day. Fruit juices diluted in water can also be good to drink. Alcohol and drinks containing caffeine dehydrate the body and should be avoided.

In general, the dietary guidelines for managing IBD include:

• Eat smaller meals to reduce the load on the digestive tract.
• Eat more regularly to maintain calorie/energy needs.
• Avoid trigger foods.
• Eat more simply or blandly, avoiding spices.
• Limit foods containing insoluble fibre (seeds, nuts, beans, leafy vegetables, fruit).
• Reduce the amount of fried, greasy and high-fat foods.
• Keep hydrated and avoid alcohol and caffeine.

Examples of recommended foods and foods to avoid include:

Resources

The Crohn's and Colitis Foundation of America (CCFA) has a very useful booklet describing the impact of IBD on maintaining healthy nutrition, how diet can impact your disease, tips for managing IBD with a healthy diet, and other resources including sample meal plans, recipes and a food journal template and is available here.

Other useful websites include:

Crohn's and Colitis Foundation - I'll Be Determined
https://www.ibdetermined.org/ibd-information/ibd-diet.aspx

Guts4life
http://www.guts4life.com/living-with-ibd/lifestyle-matters/living-healthily

Diet and nutrition for children with liver disease

Children and infants with liver diseases are at an increased risk of malabsorption, under-nutrition and nutritional deficiencies. They often have a high energy requirement, disordered or faster metabolism, inefficient energy use and increased respiratory effort. They may also have a poor appetite for a number of reasons including enlarged liver and spleen reducing the amount of room for their stomach causing them to feel full quicker, unpalatable formula or diets, or frequent hospitalisation.

Appropriate and ongoing nutrition management is vital in providing optimal care and preventing further damage to the liver. The Children's Liver Disease Foundation has a useful guide for the nutrition of infants and children with liver disease.

Nutrition management

Nutrition management needs to be individualised and is dependent on the presenting liver disease and symptoms, whether it is acute or chronic and what concurrent medical management is required.

Sara Clarke, Senior Specialist Dietitian at Birmingham Children’s Hospital explains that dietetics are essential in the management of paediatric liver disease as there is the “added complication that the body has increased nutrient requirements associated with chronic disease and may be unable to absorb all the nutrients it needs from food.”

The role of a dietitian is to monitor the child, offer advice, track progress and take measurements of the child's weight, height, body fat and muscle development to assess whether the child is growing as they should. They can then advise on the optimal nutrition to promote growth, improves immunological status, and maximise the success of liver transplantation.

Feeding method

All infants should be encouraged to feed orally where possible, and solids should be introduced at 6 months and encouraged to support the development of the child's feeding skills. However if the cholestatic infant has poor oral uptake and are unable to meet their energy needs and maintain growth, feeding via a nasogastric (NG) tube is very effective, particularly if the child is too sick to eat. Although the parent may wish to continue to feed the child orally, NG feeding can overall reduce parental anxiety and increase the well-being of infants as their nutritional needs are consistently met.

Diet

Children with liver disease are prone to malnourishment, thus a high-calorie diet with energy intakes of 130-150% of normal energy intake is suggested. This can be maximised by including high-fat and high-carbohydrate foods, as well as additional regular snacks.

They are also likely have interrupted or absent bile flow (cholestasis) and malabsorb fat so a high-fat diet is recommended. Essential fatty acids (EFA) may need to be supplemented. In formula-fed infants this can be achieved using walnut oil. Older children can increase their EFA intake by adding canola, sunflower and soybean oils to their diets, as well as eating more fish and eggs. Oil adds calories and is easier to digest without bile than other types of fats.

Dietary supplements may also be required, particularly for the fat-soluble vitamins A, D, E and K to avoid deficiencies. Medium-chain triglyceride (MCT)-oil can also be added to foods, liquids or formula to help improve the absorption of nutrients. If infants refuse the formula, small amounts of flavouring such as vanilla essence or golden syrup can be used to initiate bottle-taking and reduced once the infant is feeding well.

When reaching adulthood, it would be advised for the affected person to not drink alcohol without consulting their dietitian or healthcare professional first.

Post liver transplant

Once a child has had a liver transplant they should re-discover their appetite and most can go back to a normal diet. This will involve making lower fat, lower calorie choices than before to prevent them from becoming overweight. Vitamin supplements may still be required as some medications used to prevent the body from rejecting the new liver can affect calcium and magnesium levels.