When the dietary intake has been in excess of dietary requirements for a long period of time, diet-related diseases and disorders can develop. Other risk factors that may increase the development of diet-related diseases include lack of exercise and a genetic predisposition to the disease.

High fat intake

Excess saturated fats, carbohydrates, alcohol and proteins, are all converted to fat. Energy produced from the food consumed is used by the body for basal metabolism, physical activity and a small amount for the specific dynamic action of food.

When too much food is consumed, the individual can increase their physical activity to use up this extra energy, or it will be converted to fat and stored in the body. A small excess every day will add up over a year, unless the extra energy is used up. To maintain good health, adults should balance energy intake with energy output.

Physical activity uses up extra energy which would otherwise be converted to fat and stored in the body

Mature-onset diabetes

Age specific death rates for diabetes by sex, 1996

Mature-onset diabetes is another disease of concern internationally. The risk of developing non-insulin-dependent diabetes mellitus (NIDDM) increases with age, probably due to a reduction in the production of insulin and other hormones.

Preliminary research suggests that people who eat smaller meals more frequently, rather than two or three larger meals a day, may be protected from developing NIDDM.

High sugar intake
This is linked to total excess energy intake.
Diseases and disorders
Dental caries in children and adolescents and diseases and disorders shown above.
Change required
Decrease the intake of refined sugars and replace them with fruit and complex carbohydrates.

Low fibre intake

Diseases and disorders

Constipation, diverticular disease, haemorrhoids, a possible link to cancer of the colon.

Diverticular disease results from a diet which is low in plant foods. When intake of dietary fibre is high it adds bulk to the contents of the colon and holds water so that waste products from digestion remain soft and pass quickly out of the body. When the fibre content is low, less bulk is present and the water content is low, requiring more muscular effort to push the wastes through the colon.

This increased pressure can lead to stretching of the muscular walls of the colon. If pouches form in the walls, some of the waste products can be cut off from the main passageway. Eventually, the pouches will become inflamed and cause discomfort.

Colorectal cancer rates as the second most common cancer among the Australian population. The incidence of cancer increases with age and it is rarely seen in people under the age of 40 years. Bowel polyps can be detected by testing. Families where there is a history of colorectal cancer are advised to have regular checks for the presence of polyps. Apart from the genetic predisposition, other causes of colorectal cancer appear to be diet related.

There is much evidence to suggest a diet high in plant materials and low in meat and other animal products protect against this cancer. Phytochemicals obviously play an important part in protecting against colorectal cancer.

Change required

Increase the intake of fruits, vegetables, especially legumes, wholegrain bread and cereals. Decrease the intake of processed foods.

High sodium (salt) intake

Diseases and disorders

Hypertension (high blood pressure) can lead to more serious diseases such as strokes, coronary heart disease and kidney failure. It is associated with a high salt intake, though there are many other factors that predispose towards hypertension, such as genetics, excess weight, obesity, high alcohol consumption and low levels of physical activity.

Oedema results from an imbalance in the electrolytes that control the movement of substances into and out of cells. It is recognised as a bloated appearance in the abdominal area, face, hands and feet. Oedema is commonly associated with low protein diets, especially in young children in developing countries.

Change required

Reduce the intake of processed foods and salted and cured meats. Avoid adding sauce to foods and cut back on potato chips and other similarly salty snack foods. Choose low-salt varieties of bread, margarine and other foods. Try to lose the acquired taste for salt.

High calcium intake

Refer back to calcium in the section on nutrients. High calcium intake can interfere with the absorption of other minerals, increase the incidence of kidney stones and is usually related to excessive intake of milk. Too much milk in young children can replace other essential foods in the diet.

Change required

Milk needs to be reduced to recommended levels for age. Increase water intake and possibly decrease intake of other milk products such as yoghurt and cheese.

Low calcium intake

Many factors interfere with calcium absorption, which reduces the amount of calcium absorbed from the food consumed. Factors include a high protein intake, phytates and oxalates present in some cereals and vegetables and a reduction in stomach acids.

Factors that promote calcium absorption are the presence of Vitamin D and lactose, the secretion of certain hormones, the presence of phosphorus and the ingestion of calcium with a meal that improves stomach acid.

Diseases and disorders

May prevent growth potential being reached in children and early adolescents. Bone density will be low. This could increase the chance of developing osteoporosis in later life.

Osteoporosis literally means porous bones. During the ageing process, more calcium leaves the bones than is taken up by the bones so the bone tissue becomes weaker. Dense bones will contain more calcium and will take longer to weaken. Weak bones are more susceptible to fractures.

The incidence of osteoporosis is greater in females than males, as females lose more calcium at menopause when oestrogen production ceases. Females usually have smaller skeletal frameworks than males and have often engaged in less physical activity than them. Excessive alcohol intake and cigarette smoking also contribute to greater calcium loss.

Change required

Increase the intake of milk (low-fat is acceptable, except for young children) and add yoghurt, cheese and tofu to the diet. Most of these foods also contain significant levels of saturated fat. If the diet is already high in fat, look at ways of reducing fat intake as well as increasing calcium.

keep up regular physical activity.

Low iron intake

Diseases and disorders

Lack of attention, low energy levels, reduced ability to learn, interferes with the ability to think and reduced resistance to infection.

Change Required

Include a small amount of red meat in the diet at least every two to three days. Eat three to four eggs a week. Eat more legumes and dried fruits. Fish and chicken have smaller concentrations of iron than red meat so it is important to try and include some red meat in the diet.

Red meat does not have to be eaten as 'a piece of steak'. Minced red meat can be made into hamburgers or a sauce for pasta. Small quantities of beef can be used in stir-fry dishes and casseroles. Liver sausage (liverwurst), a delicatessen product, makes a tasty sandwich filling.

Excess weight and obesity

Increased weight leads to greater wear and tear on joints, higher risk when surgery is required, problems becoming pregnant and difficulties during pregnancy.

Cardiovascular disease

Cardiovascular disease is a term that covers all the diseases associated with the heart and blood vessels.

The three main diseases are coronary heart disease, stroke and peripheral vascular disease. Of most concern is atherosclerosis where fatty deposits, due largely to excess cholesterol line the blood vessels, reducing the flow of blood through them.

This slows the supply of oxygen to cells in the body. It is most serious when it affects the blood supply to the heart resulting in a heart attack, or to the brain that results in a stroke.

Important factors in diabetes

The glycaemic index of foods using a scale where glucose = 100

Two dietary factors appear to be important in diabetes:

The amount of cereal fibre in the diet.
The glycaemic index (GI) of the diet. Studies show that diets with a high glycaemic index and low cereal fibre content increase the risk of developing NIDDM by two to three times. Diets with greater amounts of both cereal fibre and more slowly digested carbohydrate appear to reduce the risk of NIDDM.

Glycaemic Index is a measure of the time it takes for carbohydrate in the diet to be digested and absorbed and then of raising the blood glucose level.

Changes required for diabetes sufferers

Change of lifestyle is thought to be the main cause of the increased incidence of NIDDM in the indigenous population. There is an improvement in diabetes when the traditional diet and lifestyle replace the existing poor quality Western diet of refined carbohydrates, low intake of plant foods and low levels of physical activity.

Similar observations have been made amongst the indigenous population of Canada and in the Pima Indians who live a traditional lifestyle in a remote part of Mexico. Their lifestyle is characterised by hard physical labour cultivating fields in a mountainous terrain. Their cousins who live in Arizona are overweight and exhibit a much higher incidence of diabetes.

NIDDM leads to a reduced life expectancy. Complications involve the kidneys, nerves and arteries, poor circulation especially to the feet and loss of sight.

Changes required

Reduce the intake of fatty foods or foods with highly refined carbohydrates and increase the intake of fruits and vegetables. That means a decreased intake of pastries, biscuits, cakes, chocolate and other high fat/sugar foods.
Grill rather than fry foods.
Avoid adding fat spreads to breads or spread these very lightly.
Increase intake of fruits and vegetables, whole grain cereals.
Increase regular exercise.

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