|Food guidelines such as RDIs are falling short of the latest studies into optimum nutrition with a likely impact on our rates of chronic illness, says Peter Dingle PhD
Despite passing years and millions of dollars spent, the Government sponsored (and industry influenced) food guidelines are not changing food consumption patterns - many people do not meet current dietary recommendations,(1) and fruit and vegetable consumption (which is linked to greater protection from chronic diseases) remains low.(2,3)
Two in three people in Australia don’t eat the recommended intake of fruit, and four in five are not consuming the recommended vegetable intake, with children consuming less fruit and vegetables today than a decade ago.(4) A recent UK Food Standards Agency report found that among adults between the ages of 19 and 64, only 13% of men and 15% of women eat the recommended five portions of fruit and vegetables every day. At the present time, only 32% of Americans consume five servings of fruit and vegetables per day with only 20% of adolescents meeting this goal.(5) Instead, our diet is being replaced with significantly increased amounts of sugar,(6) refined carbohydrates(7) and processed fats.
While food guidelines aim to be simplistic to reduce confusion this often fails. The food guidelines are too general for chronic disease prevention; if the guidelines were adjusted to be more specific, chronic disease risk could be reduced.(8,9,10)
A similar problem occurs within the food pyramid, which was developed in 1992 by advertising and marketing researchers to develop an image the consumer could identify with and easily understand. The pyramid was then widely distributed and has been used as an educational tool, a basis for dietary assessment, and part of policy documents. It has succeeded in creating high levels of consumer awareness and is recognised by 67% or more of American adults.(11)
This wasn’t the first time that government and industry had made attempts to influence how Americans eat; the first US guide, 'Food for Young Children', dates back to 1916. And the 'four food groups' developed in the 1950s were strongly influenced by the food industry - after all, the regulators invited the food industry to help shape the guidelines. To highlight the strong influence of industry on US food guidelines, in 2011, the US Department of Agriculture, the same organisation that created the food pyramid, labelled pizza as a vegetable because it has tomato paste. Any wonder the food pyramid was so wrong.
The 1992 food pyramid encouraged consumers to eat a huge amount of breads, cereal products and potatoes. This could very well have resulted in a greater risk of chronic disease (including CVD, obesity and type 2 diabetes), due to the fact it lacked emphasis and detail on the recommended type of carbohydrates.(13,14) This resulted in consumer confusion(15,16) and poor eating habits.(17) Food guidelines, such as the food pyramid, advocate bread consumption numerous times a day.(18) Bread is a contributing factor to a higher glycaemic load, promoting chronic diseases such as obesity, type 2 diabetes and cardiovascular disease.(19,20) Therefore bread consumption should be limited or even eliminated to promote better health. In the Australian Guide to Healthy Eating,(21) it is recommended to eat plenty of cereals (including breads, rice, pasta and noodles), but we did not evolve eating these foods.
In 2005, the food pyramid was revised into an abstract version of a pyramid called MyPyramid. This new pyramid still encouraged the consumption of grains; one of the differences was that it advised consumers to choose grains that have the word 'whole' in front of the grain name. Sure it changed a little, but not enough to reflect what we should really be eating. The Harvard School of Public Health made a scathing criticism of this iteration of the food pyramid.(22)
In 2011, the US Department of Agriculture replaced MyPyramid with a new icon called MyPlate. The plate is divided roughly into quarters, with the largest section again being grains. Dr Andrew Weil, founder of the Arizona Centre for Integrative Medicine, wrote, “there are some conceptual chips and cracks in this new dinnerware. Overall, I fear another opportunity has been lost to give Americans the best up-to-date information about what constitutes an ideal diet.”(23) Dr Weil offers as an alternative the Anti-inflammatory Food Pyramid, which promotes optimum nutrition and thus optimum health.(24)
Another area of concern is the Recommended Daily Intakes/ Allowances (RDI/As) also known as the percentage of daily values on the side of your breakfast food packet, depending on the country in which they are used. As nutritional research and knowledge evolves, food guidelines can become redundant if updates and revisions are not continually made. The Australian RDIs have been updated only a few times since 1954, yet the Japanese, Canadian and US dietary recommendations are updated every five years to match the current scientific research.(25-28)
By updating food guidelines in line with scientific research, chronic diseases can be reduced.(29) At the same time, not updating with current research may result in ineffective food guidelines that misinform and fail to protect the public. An example is the change in recognising the importance of omega 3 essential fatty acids for chronic disease prevention. In the 1960s, it was thought that both omega 3 and omega 6 were equally important. More recent research highlights the importance of omega 3 over omega 6(30) and that we are consuming far too many omega 6 oils in our diet. A food guideline that is updated regularly can make the necessary changes to promote omega 3 over omega 6; however, if updates are not made regularly, the health of consumers will suffer.
Recommended Daily Intake/Allowance (RDI/A)
Many professionals suggest that our food is acceptable because it provides the RDI. This argument has probably led people to eat poor quality food and think that’s okay. The Recommended Dietary Intake (RDI) values were established by authorities more than 50 years ago with the aim of preventing gross nutrient deficiency diseases such as scurvy and beriberi. They provide the equivalent of the nutrient bare minimum, the lowest common denominator for health, and have no relevance at all for optimum health and the avoidance of chronic illness. Optimum health cannot be obtained by following the RDI/A. These were passable as a guideline 50 years ago but were never meant to protect us from chronic illness. Yet authorities now repeatedly refer to them as the definitive levels to achieve. They are, in fact, the lowest common denominator of nutrition and aiming just to achieve them is likely a major contributing factor to chronic illness in Australia.
The RDI system shows a serious lack of sensitivity toward individuals with elevated nutrient demands.(31) It does not allow for differences in people’s nutritional needs. Various groups, including the elderly, people who experience increased physical or emotional stress, people who are of above average body weight, or pregnant women, may exhibit elevated nutrient demands. The recommendations also fail to take into account geographic differences such as living in areas with nutrient-deficient soils or high levels of environmental pollution.(32)
Socioeconomic factors may also affect the adequacy of RDI/A values for certain groups. For example, the US Recommended Dietary Allowances (US RDAs) claim to represent the daily intake levels sufficient to meet the nutritional needs of 97% to 98% of all healthy individuals in a group. However, the homeless and poor are not healthy as groups and inadequate dietary quality has been documented in these sectors of society.(33)
Recommended intakes don’t take into account the interactions of nutrients or toxins, in particular, the synergy and the fact that a shortage of one nutrient may bring about inefficient use of other nutrients. While most people know of vitamin C’s antioxidant effects, very few are aware of the benefits of it consumed with other antioxidants. Extra vitamin C spares the destruction of other nutrients in the body.
Professor Bruce Ames, one of the most respected names in modern nutrition and one of the early developers of toxicological standards, suggests that we need to move beyond the RDI and that age-related diseases like heart disease, cancer and dementia may be unintended consequences of mechanisms developed during evolution to protect against short-term nutrient shortages. In what he calls the 'triage theory', he suggests that because natural selection favours short-term survival - to escape from a bear or survive a cold winter - over long-term health, short-term survival was achieved by prioritising the use of these scarce nutrients that are also necessary for less urgent, but just as important, functions including healthy ageing. The nutrients are allocated to short-term essential (urgent) tasks versus keeping you healthy in the long term and avoiding chronic illness. The triage theory proposes that modest deficiency of any vitamin or mineral could increase age-related diseases. This theory has important implications for determining the optimum intake of all vitamins and minerals, as well as major implications for preventive medicine.(34) Current RDAs and RDIs provide for urgent short-term requirements only and not the nutrients for important tasks and optimal health.
In his recent study of vitamin K, Professor Ames and his colleagues showed that current recommendations for vitamin K, which are based on levels to ensure adequate blood coagulation, fail to ensure long-term optimal levels of the vitamin and may accelerate bone fragility, arterial and kidney calcification, cardiovascular disease and possibly cancer. So the levels approved for the short-term do not help us to avoid chronic illness, which is the biggest burden we face in the 21st century. In another study, the same group investigating selenium reported that the same set of age-related diseases and conditions, including cancer, heart disease, and immune dysfunction and an increase risk of diseases of ageing are associated with modest selenium deficiency (35). The overall conclusion of this growing body of evidence is that optimising nutrition and metabolism will delay ageing and the diseases of ageing in humans (36,37).
Perhaps easier to understand, a well known and good example of the triage system is the pH (acid/alkali levels) of the blood and mineral balance. The optimal pH of the blood is around 7.35. If the pH varies slightly from this level, as a result of eating processed foods which increase the acidity of the blood, it dramatically affects many of the 90 or so enzyme functions in the blood. These enzymes literally do all the work, such as repair, cleaning up and transport, in the blood. If they slow down too much we get very sick and die quickly. To make sure this doesn’t happen, the body has a few mechanisms to keep the pH in perfect balance. The main mechanism is to allocate or triage alkali minerals like magnesium and calcium from where they should be working in optimal conditions, such as in the cells and in bones, to balance the pH in the blood. While this protects our urgent health requirements, it increases our long risk of chronic health conditions such as heart attack, cancer and osteoporosis as a result of the shortage of these minerals. The body allocates the nutrients for short-term survival - the 'essential' functions are protected from nutrient deficiency over other 'nonessential' functions needed only for long-term health.
It is time we rethink our nutritional advice to eliminate the vested interests and to come in line with the tens of thousands of nutritional studies that have been done over the past decades. The current standards do not represent the scientific evidence that is currently available.
Dr Peter Dingle is a researcher, educator and public health advocate. He has a PhD in the field of environmental toxicology and is not a medical doctor.
1. Ball et al. 2004
2. Ziegler 1991
3. AIHW 2002
4. Magarey et al. 2001
5. Ames 2001
6. Cook et al. 2001
7. Jenkins et al. 2004
8. McCullogh et al. 2000a
9. McCullogh et al. 2000b
10. McCullogh et al. 2000c
11. Nestle 1998
12. Chiuve and Willet 2007
13. Willet 1998
14. Weinberg 2004
15. Cotugna et al. 1992
16. Ferrini et al. 1994
17. Grifford 2002
18. Nutrition Australia 2005
19. Davis et al. 2004
20. Villegas et al. 2004
21. NHMRC 2003
23. HYPERLINK "http://www.huffingtonpost.com/andrew-weil-md/myplate-nutrition-plate_b_871045.html" http://www.huffingtonpost.com/andrew-weil-md/myplate-nutrition-plate_b_871045.html
24. HYPERLINK "http://www.drweil.com/drw/u/PAG00361/anti-inflammatory-food-pyramid.html" http://www.drweil.com/drw/u/PAG00361/anti-inflammatory-food-pyramid.html
25. Kris-Etherton et al. 2000
26. Cobiac et al. 1998
27. Bush and Kirkpatrick 2003
28. Guthrie and Smallwood 2003
29. Jacques and Tucker 2001
30. Holman 1998
31. Gopalan 1997
32. Kirchheiner nd
33. Wiecha et al. 1991
34. McCann and Ames 2009
35. McCann and Ames, 2011
36. Ames 2010
37. Ashutosh and Ames 2011