The appetite for nutrient focused healthy
eating messages in the media is insatiable. In 2014 this has been highlighted
by the abundance of messages such as ‘quit sugar’ and ‘cut carbohydrate’ in the
media. But is demonizing single nutrients really the path to a healthy diet?
Traditionally nutrition research has focused on the effects of
individual nutrients and health. While this approach has shed ample light on
our understanding of the mechanisms by which nutrients and other bio-active food
components act within the body, the messages generated from such research have
often unintentionally complicated the concept of healthy eating.
As we eat foods not nutrients, healthy eating messages
which focus solely on the presence or absence of an individual nutrient are of
limited use. Such messages do not comprehend that nutrients never act on the
body in isolation, but rather are packaged with many other nutrients within foods
which act together to influence health. For example, whole grains contain more
than 26 health promoting nutrients and bio-active components and increasingly studies
are showing that single these components do not simply act alone to protect
health, but rather in concert. This explains why the observed benefit of the
whole food package of whole grains often exceeds that explained by the action
of each nutrient.(1, 2)
In addition, a focus on a single nutrient in isolation also
overlooks the impact of the food matrix (the structure of foods when consumed)
and the overall the composition of the meal within a long term eating pattern. Each
of which plays an important role on the impact of food on health.
Clearly nutrition is a very complex system and so focusing
on a single nutrient in attempt to establish a healthy eating pattern is like trying
to build a house with one tool. Constructing a healthy diet to reduce risk of
disease across the lifespan requires a holistic, whole of diet approach as
opposed to a reductionist nutrient focused solution. With advances in our
understanding of the complexity of nutrition, health authorities and evidenced based practitioners have shifted the emphasis of dietary
recommendations away from nutrients towards foods.
A focus on food was a key objective in the development of the 2013 Australians Dietary Guidelines. The Guidelines are designed not only to provide the nutrients essential for
wellbeing but also to provide adequate amounts of the foods known to reduce the
risk of chronic disease. Underpinned by a comprehensive review of over 55,000
studies, the Guidelines encourage Australians to consume a variety of nutritious,
available, affordable and culturally appropriate foods from each of the five
food groups: grains, mostly whole grain or high fibre; vegetables and legumes;
fruits; lean meats, poultry, fish, eggs, nuts; and dairy.
In addition, with Australians waistlines increasing(3),
the Guidelines also focus on promoting a healthy weight; for the average size
person doing light physical activity, adhering to an eating pattern which
reflects the Guidelines will result in a daily reduction in energy intake and
should result in weight loss.
Despite the recent re-focus of public health nutrition to foods not
nutrients, single nutrient messages are taking centre stage in the media. Many may argue that the intent of messages such as ‘quit
sugar’ or ‘low carb’ is to serve public health and encourage Australians to
limit energy dense, nutrient poor food choices (i.e. soft drinks, pastries,
biscuits, cakes and processed take away foods). However, the blunt nature of a nutrient
focused recommendation inevitably results in vocal advocates of such messages also
taking aim at foods and food groups such as fruits, whole grains and legumes, calling
for the exclusion of these foods from the diet. This is despite the fact these
foods are backed by the scientific evidence of being linked with better health.
As a result, these nutrient focused messages
fail to reflect the evidence of the relationship between food and health.
For those not convinced, such recommendations also contradict evidence from Blue Zones, the populations around the world with the best health and
longest lives, who enjoy mostly plant based diets which include whole fruits,
whole grains and legumes – each of which appear on the banned list of the
latest quit sugar and low carb fads.
Just as past
reductionist advice to reduce fat failed to achieve its intended outcome of
encouraging people to eat more naturally low fat plant foods available at the
time, current and future nutrient focused messages will fail to address
the complex relationship between diet and diet related disease risk. Nutrition
science continues to increase our understanding of the relationship between the
food we eat and health and more often than not studies are demonstrating that
it is more about all the elements of foods acting together rather than a single
nutrient.
References
- Fardet A. New Approaches to Studying the Potential Health Benefits of Cereals: From Reductionism to Holism. Cereal Foods World. 2014;59(5):224-9.
- Parker TL, Miller SA, Myers LE, Miguez FE, Engeseth NJ. Evaluation of synergistic antioxidant potential of complex mixtures using oxygen radical absorbance capacity (ORAC) and electron paramagnetic resonance (EPR). Journal of agricultural and food chemistry. 2010;58(1):209-17.
- AIHW. Australia's health 2014 Australia's health no. 14. Cat. no. AUS 181. Canberra: AIHW.2014. Available from: http://www.aihw.gov.au/australias-health/2014/
