Im concerned with trying to force certain foods and hit levels of certain vitamins thru diet.
I dont want to take any supplements.
However, I've begun to wonder, how the studies were performed that determined how much of X and Y we need.
Were they done in a similar manner to the Fat Mistake?
Did they take into account whole food or extracted quantities?
Do they account the absorption rate, both of those little pills and food intake?
Do they account for Synergy?
Are the numbers skewed by imbalances caused by Standard American Diet.
Are they trying to overcome issues related to Poor Diet?
Are they trying to overcome issues related to Diseases caused by Poor Diet?
Is poor diet stealing away from certain minerals/vitamins that the body would need much less of?
In short, How accurate are the RDA's?
Are they as bad off in some as they were in Vitamin D?
asked byStephen_Aegis (22913)
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on June 09, 2010
at 12:03 PM
It may help to understand what exactly the recommended intakes for vitamins actually mean.
Due to normal variability the level of a vitamin needed in a population usually follows a normal distribution or bell curve. The recommended intakes are usually set at 2 standard deviations about the average so as to meet the needs of 97% of the population. So the average person needs less than the recommended and a smaller percentage would get away with much less.
The recommended intakes for a vitamin is simply a level that can be given to everyone without risk and will ensure an adequate intake for everyone. It is not meant to suggest that everyone needs exactly that amount. Also the adequate level is usually some way above that needed to prevent obvious deficiency. For example a dose of 10 mg of Vitamin C per day is enough to prevent obvious scurvy occurring http://ije.oxfordjournals.org/cgi/content/full/35/3/556 however if this is enough for optimum long-term health is a different question.
Just because someone can consume much less than the rda of a vitamin and not show any deficiency does not invalidate the science behind the recommendations and it does not mean that everyone can consume a low level and be healthy.
Were they done in a similar manner to the Fat Mistake? No.
Did they take into account whole food or extracted quantities? They are worked out from dietary food.
Do they account the absorption rate, both of those little pills and food intake? They do account for absorption rates from food when this can be measured.
It is certainly possible that major changes in diet will alter the need for certain vitamins, however this is beyond the scope of population wide recommendations and the need is unlikely to increase.
Recommended intakes for vitamins are studied in countries around the world not just the USA. They are a best estimate of requirements based on current science however there are still uncertainties as they are very complex questions to answer. This is why the recommendations are often updated They are only meant to be a useful guide not something to obsess over in detail.
on May 31, 2010
at 06:53 PM
Think about it this way ---- I would go as far as to say, that all studies on vitamins' effects on humans have been done with humans eating SAD. Meaning that the very basis underpinning the study is flawed.
Ergo, any results, no matter how stat. sig or not are likely flawed.
PS Same goes for cholesterol etc etc
on May 31, 2010
at 07:17 PM
Group Wiki of Controversial RDAs: (this is a community wiki, so click to edit, also if you see a paper in a journal that's not free, if you post it I can send it to you)
- "Because of the lack of sensitive indicators of zinc status, the estimation of a zinc requirement for adults and the setting of a recommended allowance is beset with several uncertainties" Paper says zinc in red meat = most bioavailable and people not eating it likely to be deficient.
Factors that could influence paleo differences:
- High amount of sugar or antinutrients could leach nutrients away, leading to recommendations that are too high
- But often recommendations calculated from a norm based on people on SAD, so might be too low
- Our diet includes more bioavailable forms of certain nutrients like retinol vs. beta carotene or ALA vs. DHA, zinc
- Genetic differences: known variability includes DHA and retinol synthesis
on May 31, 2010
at 04:39 PM
I think its safe to assume you can throw out any and all RDAs for vitamins that were established by the FDA. The FDA has had their time in the sun, let it pass, and riddled it with bad science, poor funding, and border line corruption from Big Agriculture, and Big Pharm.
As Paleo/Primal types, I think we need not initially concern ourselves with what % of vitamins we are consuming. If we are eating whole foods of high quality, that should take care of any percentages and/or deficiencies.
What we should be concerning ourselves with is systemic inflammation, which is behind damn near every disease we are fighting now a days. And which is VERY hard to control when switching over to Paleo/Primal.
I've noticed when people initially go Paleo/Primal, they begin eating too many nuts, too much CAFO meat, allowing seed oils to still remain in the diet, too much fructose, etc. They dont realize how important systemic inflammation is, and how it is truly the silent killer of all of us.
Sorry for the bit of off-topic rant, but I think everyone needs to concentrate more on the massive O3:O6 in balances that we ALL have to some degree, instead of % of Vitamins.
on June 10, 2010
at 09:25 PM
RDAs are a lowball average for the general population. Everybody is a little different, so RDA could be a starting point, but the final word. Also, science is continually finding out more information about proper nutrition. In other words, the "experts" who come up with the RDA standards are only guessing a lot of the time. Part of the reason I started the Primal way is it makes sense. Following the evolutionary path, you should be getting most of your vitamins, in proper proportions from your food.