I've never understood why the human nutrition folks have created such unnecessary confusion. I've been told the goal was to make things simpler and easier for the layperson to understand, but the success of that is dubious at best.
Natural selection means some get left behind. Humans work very hard to avoid that.
And you believe that none are? When did the death rate for those under 80 reach zero? I some how managed to miss the announcement! [/sarcasm]
Of course humans work to avoid that. That doesn't make them 100% successful at it. Plenty of people die before or without reproducing, and those people were "selected" against whether as a result of disease, war, bad luck, lack of desire to have children, or their own stupidity. We are not as heavily culled by "natural" events as we might be, or once were, but that only means that we've increased our genetic diversity.
Some of those genes have demonstrable down sides, but it is common in evolutionary studies to see a widening of the gene pool when selection pressure is reduced. This is a natural part of evolution as the species begins to differentiate to take advantage of different ecological niches. Furthermore, there are most definitely internal selective pressures at play as well.
Western countries have become nuclei of successful people, with hot bed (like silicon valley) acting as concentrators of certain phenotypes (the stereotypical borderline and high functioning autistics that are the engine of computing progress). That those traits may have been an evolutionary disadvantage in pre-computing days does not change their current value today, or their current effect on those individuals chances of reproducing.
Diabetes, cancers, gastric disorders (Celiac, e.g.), endometriosis, fibromyalgia, and any number of other increasingly common disorders would contradict that
1. Diabetes is no longer fatal, and many who have the more mild form could control it without insulin if they just ate a healthier diet.
2. Cancer has always existed for those who live long enough
3. gastric disorders, if not fatal or don't reduce ones chances of reproduction, are not inherently relevant to survival even without modern medicine
4. endometriosis, has also always existed. it can be seen in non-domesticated species
5. fibromyalgia is vague pain. Again, pain by itself is not fatal and does not reduce ones odds of reproducing even in the absence of modern medicine. Especially if it frequently does not occur until one is past their prime reproductive years.
6. poor eyesight has not been a selection pressure in centuries, even before the development of optics or the widespread availability of corrective lenses. Again, especially in those cases where it does not appear until after the person has passed their prime reproductive years. Most people who wear glasses at younger ages do so to correct relatively minor defects in their vision.
7. IVF has risen in prevalence in part due to changes in human culture. Many women who might have been able to conceive naturally in their teens and 20's need IVF in their 30's and 40's because of non-genetic problems, and therefore are irrelevant to the discussion of selective pressures.
Whether that's a gene that results in sickle cell or juvenile diabetes or whatever, that's what I mean by a "bad gene".
Being heterozygous for sickle cell is a BENEFIT if you live in a malaria rich region of the world, so to categorically state that it is "Bad" is myopic. This is exactly the point I've been trying to drive home. The value of a phenotype is situation dependent, and just because it confers no benefit in one situation does not mean it could not under different circumstances. The sickle cell trait spread as widely as it did in African populations in spite of the problems being homozygous for the trait can cause because the heterozygotes were better adapted to frequent exposure to malaria.
Tell a child with leukemia or diabetes that his "trait" is actually beneficial in some way. Tell someone who is badly nearsighted and can't see anything without glasses that his trait is beneficial in some way. Tell the child who is born with a cleft palate that you aren't going to do cosmetic surgery because his trait is actually beneficial.
In the current environment, no none of these are beneficial. However, that does not mean they could not be under the right conditions or when paired with other genes in a different individual. Also, cleft palate is not always genetic in origin. Far more of those who develop a cleft palate have no genetic predisposition and they could have developed the phenotype due to environmental reasons (maternal nutrition, physical trauma, exposure to a chemical that interferes with midfacial development. Furthermore, evolution is not about the individual, but the species. Using the Sickle Cell example again, homozygotes with the sickle cell allele generally die, but their heterozygote siblings survive much better than those who are homozygous for the non-sickle cell allele.
Let the Down Syndrome kids use their beneficial trait to make good lives on their own.
You have obviously never heard of the neurodiversity movement. I've worked with special needs kids and there are some with down syndrome that are quite capable of surviving on their own. More capable than many non-down-syndrome individuals I know.
when you remove natural selection from the process of evolution, evolution no longer works
It is exceedingly arrogant to believe that humans are somehow exempt to selective pressures. As long as reproduction rates are not evenly distributed across the entire human population (ie 2 children per couple, and all children live to have 2 children themselves infinitely), then there will be evolution as some genes become more or less prominent in the overall population. To believe otherwise is to seriously misunderstand the underlying mechanisms of evolution.
No, I really don't care, because that's so far in the past that it was before existing civilizations and thus before current efforts to defeat natural selection that it is completely irrelevant to this discussion.
No it is not irrelevant. It is an example of the loss of an ability that on it's face would be a negative (like the ability to digest lactose or gluten), yet turned out to be irrelevant to the survival of the species. You seem to operate under the false assumption that any loss in evolutionary "fitness" for past selective pressures is an unequivocal negative for our evolution as a species. However, the fossil record of all species is littered with examples of lost traits that were essential during one era, but unimportant to survival later on.
For human nutrition, because it is so open to anyone who can write a good book and can look surprisingly healthful for their book jacket photo, the requirements are much lower. Instead of formulating nutrition plans (left to the RD's) human nutritionists are generally the charismatic front (wo)men who the brand is built around, and who's job it is to spout BS on the talk show circuit and in infomercials.
By active gene manipulation through selective breeding.
True, and that is why we've made so much progress in such a short period of time with pigs. However, to assume that natural selection cannot accomplish in 4000 years, what we've done through selective breeding in ~40 years is odd to me. In humans there isn't some intelligence applying the selection, but that does not mean that selection is not taking place. The difference is that the environment, consisting in part of the food that can be cultivated in that environment, is applying the selection pressure. Most humans can utilize lactose well into adulthood because we evolved the ability to do so because the offspring of humans who could were more likely to survive and breed. The ability to digest lactose as an adult is not as advantageous as it once was, and in the absence of that selective pressure the trait is becoming less universal. Both the historical spread of lactose tolerance and the current rise of lactose intolerance are examples of evolution in action.
What we HAVE been able to do by avoiding eugenics with humans while applying modern medicine is to make less robust humans
No, humans are not less robust, at least in an evolutionary sense, because evolution is all about survival in the environment as it is at the moment. It is not about some theoretical ideal or past conditions that no longer apply. It is inconvenient that one my sons is lactose intolerant, sure, but he lives in a time and place where the ability to digest lactose does not affect his long term prospects of reproduction appreciably. Similarly, it would have been nice for early sailors to be able to synthesize vitamin C on their own, but they couldn't and that led to a lot of brave men suffering and sometimes dying of scurvy before they realized that eating citrus fruits or extracts can prevent it (even before medicine realized what it was about citrus that prevented scurvy). Humans have always used our intelligence to think our way out of apparent maladaptions to our environment. The net effect has been to show that our greater intelligence is a more valuable adaptation that big teeth, claws, and a vitamin C synthetic pathway in the liver.
...has kept people with bad genes alive...[emphasis mine]
There are no "bad" genes. There are traits which are not well adapted to a particular environment or situation, but that does not make them bad per se. Sickle cell being the poster child for an apparent disorder this actually advantageous under certain conditions. Same goes for white skin, and advantage that evolved and spread in colder northern europe, but is a hindrance to whites living in regions with plenty of UV exposure throughout the year because it increases your risk of developing cancer. All traits are trade offs and to assume any trait is inherently "Bad" is to fall into the same faulty reasoning that led to eugenics in the first place.
What you are seeing is the survival of detrimental mutations or maladaptations, not natural selection against them.
Evolution is not directional. There is not De-Evolution as a counter to Evolution. There may be a future environmental condition where the current maladaptation are favorable. Evolution is the accumulation of genetic changes over time, its not the accumulation of abilities like in an RPG. Shortly after humans evolved tricolor vision we started loosing the ability to detect most pheromones. It is believed that this loss of a previously essential ability occurred because the evolutionary role for which pheromones had evolved (to signal sexual receptiveness among other things) could also be met by increased color sensitivity (consider the baboons with the red asses everyone likes to laugh at, or the ones with the blue, red and white skin on their faces), thus making the loss of one specific ability unimportant in the large flow of genetic changes.
My original subject line still holds be careful with those assumptions
Our ability to support the energy sink that is the human brains is dependent upon our ability to get enough nutrients, and more importantly energy, to support its development and high maintenance requirements as an adult. That it self is evidence of our diet and bodies evolving together. Also, the reduction in the size of our jaws, leading to chronic problems with impacted 3rd molars, is another instance where we have evolved as a result of our diet. The larger jaws of earlier hominids are not necessary because we cook our food. That cooking makes the nutrients more available, meaning we need to eat less. It also makes the food softer, meaning we don't need massive jaws to constantly grind seeds and roots and raw meat.
There is plenty of other evidence that our bodies have evolved in large part BECAUSE of changes in what we eat and how we prepare it. The problem is that fad dieters have never been very big on reading peer-reviewed literature. They prefer to read the book-of-the-month endorsed by some celebrity or health guru.
We've seen human populations with distinct difference in their ability to handle different components of foodstuffs (lactose, gluten, fat, etc). Explain to me how that ISN'T evidence of evolution! The whole "paleo" fad is based on two false assumptions. 1) that we are no longer evolving, and 2) that evolution is directed at some idealized collection phenotypes.
I don't care what you want to put in your body. I expect the same respect from you.
Wow, you have a very carrying soul [/sarcasm]
Unlike you, the FDA has a statutory obligation to make sure that foods and drugs sold in the US are safe for their intended use. The "intended use" part allows for a surprising amount of wiggle room. How is the FDA to know if you bought vitamins to treat some disease (a drug use) or to make sure you meet the normal RDA (not a drug use)? They can't and don't try. The intended use limit is not on the end user, but the seller. VitaminsRUs cannot advertise that their vitamin pills prevent cancer, but if you believe they will there is nothing the FDA can do to stop you, and they won't even try.
You do not have the moral authority to tell another person what they may or may not ingest.
The FDA is not a moral authority, but a scientific one. They are staffed with experts in various fields necessary to decide which products are safe and effective, and which are not. You appear to feel yourself up to the task of sorting the wheat from the chaff, but most Americans are not. I'm going to go out on a limb here and guess that you consider yourself to be of above average intelligence and education (ironically, the vast majority of people do as well). But think about most of the people you see in a day (neighbors, friends, family, strangers). How many of them would you suspect are similarly equipped to handle sophisticated marketing made to give the appearance of scientific validity despite a demonstrable lack there of? That is why the agency was created (see patent medicines, most of which were simply different forms of cocaine). To protect the largely ignorant populace from unsafe and unproven products.
As I stated before: regulation to ensure the product contains only the labeled, unadulterated ingredients is the limit. I can also conceptually support banning "false claims" but that is a very squishy concept in biomedical terms and is typically advocated as an subterfuge to ban things.
All such regulations require oversight. Verification that companies are obeying the laws that are supposed to govern their actions. The dietary supplement market is exempt from much of this oversight because they lied to the US population and convinced them that the FDA was out to take away their vitamins and make they by prescription only. That would never have happened. I know this because I do regulatory work with the division of the FDA involved in regulating the animal equivalent to dietary supplements, namely Feed Additives. No prescription is needed for an approved feed additive, no consultation with a veterinarian is required, but feed additive manufacturers are required to prove that a new additive is safe and effective. Once approved, anyone can sell that feed additive for the approved use without further involvement of the FDA. A feed additive petition takes about 2 years (on average, with a HUGE SD due to a non-normal distribution) from submission to approval, but once the approval is made no more work is required. In most other countries the requirements are similar, except that approvals are vendor specific (Company A and B both have to register their Vitamin C), and have to be renewed periodically (US system only requires approval once).
The food supplements industry is largely unregulated in the US due to an impressive mis-information campaign back in the 1980's which resulted in a special section of the regulations for dietary supplements. Animal feed is more tightly regulated than feed supplements. Feed additives have to prove, to the satisfaction of the FDA, that they are effective for a specific purpose. No similar requirement exists for dietary supplements.
Likewise, "companies must submit studies, and the FDA must approve them, before a genetic change may be added to a food" sounds equally reasonable and yet is labeled "zealotry" by folks like the parent poster.
As a matter of fact, the FDA is already one of 3 federal agencies in the US responsible for oversight of GMO:
FDA regulates food from GE crops in conjunction with the U.S. Department of Agriculture (USDA) and the Environmental Protection Agency (EPA). USDA's Animal and Plant Health Inspection Service is responsible for protecting agriculture from pests and disease, including making sure that all new GE plant varieties pose no pest risk to other plants. EPA regulates pesticides, including those bioengineered into food crops, to make sure that pesticides are safe for human and animal consumption and do not pose unreasonable risks of harm to human health or the environment.
What gets everyone all hot and bothered (myself included) is the erroneous perception that GMO are not regulated at all, or that they've been confirmed as unsafe for people or the environment despite all of the evidence being in opposition to that position. It is decidedly anti-science zealotry that prevents many from accepting that the scientists involved in developing and certifying GMO's have done their jobs, and done them well.
Sure it was stopped before commercialization. But this is hardly something you get when splicing.
You are flat out wrong. This is a case of why GM is so safe, and an example of the system working as designed.
Take a look at Solanine in potatoes. As a member of the nightshade family, there is always the potential that a new variety of potato will contain dangerous levels of solanine or other glycoamyloids just due to random interaction between the parent genomes. Bombarding potatoes with mutagens like ionizing radiation, or carcinogenic chemicals are OK by organic standards, and how new varieties of potatoes were developed before we even understood that DNA was the source of inheritance. This kind of genetic modification is MORE likely to result in accidental changes in Solanine concentration because so many genes are changed simultaniously. Several varieties of potatoes that were not GM have been removed from the market only AFTER they made people sick.
The targeted nature of modern techniques mean we can characterize the new strain to a previously impossible level BEFORE they hit the market. Who cares how many mistakes they make in the lab, as long as they STAY in the lab. The 78 UK made sick by Solanine poisoning in Britain in the 1970's are 78 more adverse events than have ever been reported for ALL GM products combined over the last 20 years precisely BECAUSE we scrutinize all new GM strains so closely before they are allowed on the market.