Recommended Dietary Intakes - Do You Need Supplements?
By Paul Rogers
Photo by Untitled Blue
Here’s a quick definition of RDIs — or RDAs as they are called in some countries.
Optimising Diets for Chronic Disease Risk
Other Standards in Nutrient Reference Values
- EAR (Estimated Average Requirement). A daily nutrient level estimated to meet the requirements of half the healthy individuals in a particular life stage and gender group.
- RDI (Recommended Dietary Intake). The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97–98 per cent) healthy individuals in a particular life stage and gender group.
- AI (Adequate Intake - used when a recommended dietary intake cannot be determined). The average daily nutrient intake level based on observed or experimentally-determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate.
- EER (Estimated Energy Requirement). The average dietary energy intake that is predicted to maintain energy balance in a healthy adult of defined age, gender, weight, height and level of physical activity, consistent with good health. In children and pregnant and lactating women, the EER is taken to include the needs associated with the deposition of tissues or the secretion of milk at rates consistent with good health.
- UL (Upper Level of Intake). The highest average daily nutrient intake level likely to pose no adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects increases.
- AMDR (Acceptable Macronutrient Distribution Range). An estimate of the range of intake for each macronutrient for individuals (expressed as per cent contribution to energy), which would allow for an adequate intake of all the other nutrients whilst maximising general health outcomes.
- SDT (Suggested Dietary Target). A daily average intake from food and beverages for certain nutrients that that may help to prevent chronic disease.
Dietary Supplements
Supplementation has a role to play, but it needs to be done with caution, restraint and knowledge. The bottom line is that there will be individuals and population groups that do not meet the RDIs for individual nutrients.
- This can result from poor nutrition practices or even special diets poorly implemented. Low-carbers could be short on fibre and vitamin E; vegans on zinc, iron and B12; and very low-fat dieters on long chain omega-3.
- Populations in nutrient poor regions might lack iodine and selenium; and certain cultural habits like full body clothing can result in inadequate vitamin D intake in the absence of food or supplement sources.
- Athletes and heavy exercisers may need a modest increase in some nutrients, but this is usually accounted for by increased calorie intake — as long as the extra food is nutrient dense for the most part.
- Older people absorb vitamin B12 less well and this may require supplementation. The ill or infirm who do not get adequate sun exposure may require vitamin D supplements.
- Pre- and during pregnancy, folate supplementation is a useful reassurance against neural tube abnormalities.
However, not only is it likely wasteful to take mega-doses of supplements, it may even be unsafe. The recent scientific examination of vitamin E and beta carotene in high supplement doses has not yielded promise and has suggested adverse effects. If you feel you need to take an individual supplement or a multi, first check out the excellent information at the Office of Dietary Supplements at the NIH. then try not to exceed the RDI by more than a few times for any individual nutrient, unless there are indications that it’s safe and effective to do so.
The Truth About Organic Food
By Paul Rogers
Photo by bittenword
I’ve been a keen gardener most of my life, following a strong family tradition. We’ve grown everything from flowers and ornamentals to fruit trees and vegetables — with varying measures of success. Organic growing in a home garden, and wherever feasible commercially, just seems like sensible environmental management to me . . . and it’s especially applicable to home gardening. I’ve also written about organic growing and been a member of a growers group for decades.
Organics may not be the only solution
Even so, I’m not an absolutist, and I am a pragmatist . . . I accept that there may be other farming and cultivation systems that could indeed be regarded as “sustainable and healthy” even though they may not pass organic certification. But that’s not my argument here. I’m going to look critically at the notion of why you should buy organic food and whether the advantages stack up — give or take a few generalisations.
Here are the usual reasons for supporting organic food production:
- It’s healthier because few, and low-toxic pesticides are used and residues on crops are not a problem
- It’s healthier because organic food is higher in dietary nutrients
- It’s more sustainable because soil is managed better without chemical fertilizers
- It’s safer and sustainable because beneficial organisms like bees and predatory organisms and wildlife are not poisoned by pesticides
- It’s safer because humans are not poisoned by pesticides as they use them.
Pesticide residues
Even allowing for cheating, it is clear from testing that organic food has fewer residues of detectable pesticides than non-organic food. The issue is whether the presence of residues in non-organic food is a health hazard. Clearly, in some cases it is. The cases of aldicarb pesticide poisoning from melons in California is a classic case. This was only detected because of the severe symptoms. Many other cases are likely in which the victim has less acute symptoms and the cause remains unidentified. And, the effect of long-term exposure to small quantities of residues is unknown, but could be significant.
Testing for safe food. With the world food supply increasingly traded across borders, ensuring “clean” food by monitoring it for contaminants has become increasingly difficult. Recent issues in food safety in relation to food products imported from China make this all too clear.
Organic food has more nutrients
This is the one the professional agriculture, health and nutrition communities have resisted so strongly for so many years. In essence, it is a complex issue. To measure this accurately, you really need to set up controlled growing conditions for a reasonable comparison, and even though quite a few early studies showed advantages for organics in some nutrients like vitamin C, iron, omega-3s and a few other minerals, the design was often somewhat amateurish — until the European Union Newcastle University study came along. Read the results here: “Organic produce better for you”.
Variability abounds. The authors caution that variations in qualities exist across the organic and non-organic spectrum. What this might mean for you, as a purchaser, is that a badly grown organic apple could very well be inferior to a well-grown non-organic apple. One might expect that across a continuum of organic produce, the nutrient value may be higher, but don’t expect that any one purchase will give you that guarantee.
Phytonutrients finally. Over the years of this organic nutrient debate, the one thing that has mostly been absent is an evaluation of the non-vitamin and mineral nutrients. These are the antioxidants, the polyphenolics, carotenes, sulphur compounds, the omega-3s and many more that are known to be health-giving principles in foods. Finally, this also seems to have been answered. In the Newcastle University study:
They found levels of antioxidants in milk from organic cattle were between 50% and 80% higher than normal milk.
This is not surprising, overall, because Alyson Mitchell, associate professor and food chemist at the University of California, Davis, found exactly the same thing in her work analysing tomatoes. Soluble fertilisers, especially nitrogen, and strong pesticides may inhibit the plant production of phenolic compounds. See Mitchell again for a discussion.
One would have to say that early professional bias against the idea of organics having higher overall nutrient values, in a dietary sense, seems to have been ill-founded and perhaps influenced by various vested interests. However, this should not suggest that eating organic foods, even with a premium supply of antioxidants, results in superior health outcomes: that is yet to be proven.
Organic growing is more sustainable
As a general rule this is probably true, and is likely to be more so for smallholdings rather than large commercial enterprises. The definition and evaluation of “sustainability” is variable, but one issue is the recycling of inputs to the system versus importing inputs like organic fertilizers from elsewhere. Sustainability is about being able to make systems last without degrading the system.
Nevertheless, several recent studies — University of Michigan, the USDA and the FAO and others, have found that organics actually outperform conventional agriculture in measures of soil sustainability and biological sustainability — and may even approach the production efficiency of non-organic farms in some cases.
Safer for wildlife and diversity
New Scientist reports: “Organic farming boosts diversity”.
Organic farming increases biodiversity at every level of the food chain – all the way from lowly bacteria to mammals. This is the conclusion of the largest review ever done of studies from around the world comparing organic and conventional agriculture.
Enough said about that one.
Occupational health and safety
This is the sleeper issue in organic production. It receives less attention than other aspects. The human health legacy of toxic pesticides in developing nations has been monumental. And even in the developed nations, the misuse and overuse of pesticides has resulted in substantial impacts on human health. The US Agricultural Health Study has reported on some such results.
Here is what esteemed toxicologists Levine and Doull said about pesticide poisoning worldwide in 1992:
Global estimates of acute pesticide morbidity and mortality. Levine RS, Doull J. Rev Environ Contam Toxicol. 1992;129:29-50.
Mathematical models have projected increasing numbers of pesticide poisoning throughout the world, rising from 500,000 cases/yr in 1972 to 25,000,000 cases/yr in a 1990 estimate.
Summing up
Organic food is more expensive; you have to decide if it’s worth it. In addition, the science of organics is a bit fuzzy at times. Some modern pesticides actually have lower toxicity than approved organic pesticides. The more popular and affordable organic food becomes, the more we will see mainstream food manufacturers taking advantage of it. No folks, the organic pop tart is not a health food. Overall, though, organics is a neat package of environmental health and safety practice. I support it strongly.
Why You Need to Eat Your Greens
By Paul Rogers
Spinach pic by Moria
Green leafy vegetables like spinach, lettuce, Chinese vegetables, kale and many others are part of the evolutionary heritage of primates — and humans are no exception. Eating carefully selected green leafy plants for millions of years must have made human biochemistry beautifully adapted to these foods. Too bad many of us don’t eat enough.
They contain valuable vitamins and minerals and antioxidants including iron, lutein for the eyes and other carotenoids, magnesium for heart and muscle, folate for the heart and pregnancy, vitamin K for bones — and one nutrient that regularly gets overlooked: the plant form of omega 3 called alpha linolenic acid or ALA, which is not to be confused with the other polyunsaturated fat called linoleic acid. ALA is a shorter chain length omega 3 that the body can covert to the longer chain EPA and DHA or fish oil omega 3s. ALA is also found in walnuts and canola oil.
The other omega 3
ALA also seems to protect us from heart disease like it’s longer-chain relations EPA and DHA. In fact, that’s how animals get EPA and DHA — from eating green grass and leaves and converting ALA. And that’s why free-range beef or chickens feeding on natural grass and litter are healthier to eat than lot or coop feed animals.
What to eat, and how to prepare
I make a real effort to eat leafy greens regularly. I’ve settled on ones that I like and I grow them organically as well as buy from the supermarket. I eat mainly spinach, cos lettuce, Italian parsley (not the curly leaf one) and rainbow silverbeet, called chard in some regions. I live in a sub-tropical climatic zone, so the spinach tends to be seasonal, requiring colder weather. The cos and silverbeet will grow in all except the hottest times of year, with the silverbeet being pretty much perennial if you allow it to be. The parsley dies off and self-seeds brilliantly for next year.
Last seasons cos self-seeded and grew like a wheat-field. Fantastic. Pick the dark greens leaves when you need them and they just keep coming after a touch of blood and bone fertiliser. Unfortunately, the rabbits also found them. Such is life.
Spinach can be eaten in salads or cooked lightly with a little olive oil, garlic, pepper and lemon juice. Like some southern Europeans, I like a large bowl, steaming hot. The silverbeet is a little stronger and works better in omelettes and stir-fries for me. Parsley is more useful with the tough stems cut off, but then you can use in stir fries, salads, omelettes, bowl noodles and soups or just nibble.
Fresh, dark cos with lemon juice, pepper to taste and a small amount of olive or soy oil (more ALA in soy), with a little low-fat feta if you like, makes a great companion for main courses.
How greens help
Find some greens that you can eat on a regular basis and make them a regular part of your diet. If you exercise a lot you need a potent brew of natural antioxidants to ward off the oxidation products of exercise. If you’re trying to lose weight with a low-calorie diet, nutrient-rich foods are important to ensure you get your recommended daily allowance of vitamins and minerasls for good health. I prefer not to juice — you’ll probably lower the GI anyway — and supplements are pretty much a waste of time. So go greens!
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