Food Variety Update

While much nutritional advocacy has focussed on staples, this has more to do with food security for energy and protein intakes than it does for optimal health.

The focus on staples also does not encourage biodiversity, which in itself is increasingly crucial for healthy environments. The more explicit nutritional significance of achieving biological variety in one's diet is that it helps ensure an adequate intake of essential nutrients and other components, it dilutes potential adverse food factors, and it recognises the factors in food important for health which are currently not regarded as essential nutrients. These are, in the main, plant food factors, now referred to as either phytochemicals or phytonutrients.

For these reasons, the latest trend in nutrition science is more. But more means 'different', not more of the same. Variety means that we choose to eat a mixture of foods across the range of food types (cereal, fruit, dairy) and a mixture from within food types (rye, barley, wheat).

Nutrients have been thought to be the basis of good health and have formed the basis of what has become known as 'nutrient based' nutrition. More recently, nutrition scientists have recognised that food is more than just the sum of its 'nutrient' parts, mainly because of 'other' known and unknown protective components that are present. As a result, a new approach i.e food-based nutrition has become popular.

What has become clear is that there is much more to food than vitamins, minerals and fibre. Nutrition scientists have identified about 12,000 phytochemicals that play some role in preventing disease – so it makes sense to cast your food net as wide as possible to capture as many of these compounds as you can, especially as some of them may work together as a team.

The over arching nutritional issue at all ages beyond the time that we are breastfed is that of food variety. This is exemplified by the notion that a wide range of nutrient/ phytochemically dense foods in small quantities is associated with protection against macrovascular disease, greater longevity and better overall health and possibly less abdominal fatness.

There is also some new thinking on cancer – it is being increasingly seen as a disease of dietary deficiency and it is a lack of protective foods in our diet that make us vulnerable. Some protective foods may be low in nutrients, but are nearly always high in phytochemicals e.g tea.

Enough epidemiological evidence is available to justify promoting food variety as a technique to reduce morbidity and mortality, even though the mechanism is uncertain. In America, a food diversity score, based on 5 food groups had predictive power of mortality, especially in men (Kant et al. AJCN 1993; 57: 434-40).

Weekly food variety score

Research suggests that over 30 different food a week (counting herbs and spices) is more healthy than under that number. Eating such a wide variety of foods ensures a wide range of known nutrients as well as an intake of nutrient combinations and nutrients that may not yet be recognised by science as being healthy.

Therefore, when looking at the overall diet, another useful method is to consider food variety.

The food variety score does not place a value judgement on any food. This is an advantage of such an approach given that nutrition science is constantly evolving and much uncertainty still exists about the potential benefits that particular foods and their complex components (including phytochemicals) may offer. No single food can provide a nutritious and healthy diet.

Foods from similar biological sources in nature have common nutritional characteristics. Getting to know the biological sources makes it easier to remember the main nutritional properties of various foods.

A score has been developed by Savige, Hsu-Hage & Wahlqvist 1997 that measures food variety according to the biological/botanical origins of the food e.g all citrus fruits are grouped together. Foods can be added up, with each biologically distinct food group scoring only once, no matter how often the foods within this group are eaten, but a minimum quantity of about 2 tablespoons must be consumed before it can be scored.

Foods from these various sources can be scored and the total used as an indication of adequate nutrient intake.

A food variety score of at least 15 over one week is generally nutritionally adequate. A score greater than 20 over a week will virtually guarantee adequate essential nutrient intake. A score of 30 over a week or 12 in a day is considered excellent.

It is not usually difficult to reach the goal of 20 biologically different foods per week. However, for some patients in the risk groups (e.g food faddists, alcohol abuse) it is often harder. Encouraging a more nutrient/phytochemically dense diet, which is also less energy-dense, is an important part of dietary education.

At first glance this scoring system appears to favour omnivores, especially people with high intakes of animal foods, however, the strictest vegan can still obtain a very good score of >30. Japanese food guidelines suggest 30 or more different foods per day and these are usually taken in very small portions in the form of pickles, sushi.

Ideally 20-30 different types of foods should be eaten every day, but unfortunately Australians appear to eat only 15-18 different foods per week. Nowadays we have a food supply that includes a wide range of fresh and processed foods all year round with little seasonal variation, making it much easier to obtain a wide variety of foods.

Over 50 different fruit and vegetables are available at any time of the year in Australia. Herbs and spices should not be forgotten either. They have been used in folk medicine for many centuries and have many beneficial effects. To increase food variety choose foods which already provide variety, such as eating multigrain breads and natural mueslis.

To further increase variety, serve accompaniments such as salads, spreads including pesto, chutney, jams and nut spreads.

Before the discovery of phytochemicals, jams (and pure honey) were not recommended because they were high in sugar and did not contain vitamins and minerals in significant amounts. However, they contain significant amounts of phytochemicals, especially jams made with berries and citrus fruits. Many of the fruits used in jams are seasonal and jams are a method of preserving them for consumption when the season ends. Consuming a small amount of a variety of jams across the week is another good way to increase ‘fruit’ variety.

Stir fries, casseroles, soups and salads are another easy way to increase ‘vegetable’ variety by adding lots of different ingredients, especially onions, garlic, parsley, herbs and spices. Adapt traditional recipes by adding extra vegetables and legumes.

Climb out of your food rut – if eating 20 different foods a day sounds like a ‘pig out’, it’s not – you do not have to eat more. Rather than having a meal comprised of a few different ingredients in large portions (steak, potato and peas) have meals with many ingredients in smaller portions (e.g stir fry, casserole, soup). Also, don’t stick to one kind of breakfast cereal or bread, vary sandwich fillings daily and find ways to sneak in little extras e.g. add handfuls of herbs to salads, nuts in stir-fry.

Weekly Food Variety Score (foods consumed from different biological sources)	<10 inadequate food variety (and inadequate nutrient/phytonutrient intake)
	<20 marginal
	20-24 fair
	25-29 good
	>30 very good

* An intake of 12 different foods in one day also characterises a diet that is adequate in essential nutrients.

To calculate your Weekly Food Variety Score click here

Reference: Savige GS, Hsu-Hage BH-H, Wahlqvist ML. Food variety as nutritional therapy. Current Therapeutics 1997: 57-67.

Last Updated: October 2004