The CYP enzymes that were mentioned as being inhibited by glyphosate and necessary for the conversion of 25 hydroxy D into the active 1, 25 dihydroxy D form turn out to also be essential for conversion of vitamin D3* into the 25 hydroxy D form [1, 2] — so glyphosate could be the smoking gun that explains why U.S. citizens on average had lower 25 hydroxy D levels than Canadians (who presumably live farther North and receive less direct sunshine over the course of a year).
- *I have read more recently that supplements of the D3 version are active in the vitamin D receptor so it may not need the same CYP enzymes to be activated as the D2 supplement form does but the D2 form is more commonly available in supplements, double check the supplement bottle when shopping to see which type is included. See: https://www.ncbi.nlm.nih.gov/pubmed/19944755
And this could help explain why taking high doses of supplemental vitamin D has not been found effective to help raise patient’s 25 hydroxy D levels — if the person has glyphosate within their body inhibiting the CYP enzyme then they wouldn’t be able to convert the vitamin D supplement into the 25 hydroxy D form that the lab test is checking for and the supplemental form wouldn’t show up on lab tests for the 25 hydroxy form (which in normal health would then be available as needed to be converted by a CYP enzyme into the active 1, 25 dihydroxy D form whenever the active form was needed). There are multiple types of CYP enzymes with a variety of roles. Breaking down the active form, 1, 25 dihydroxy D, also requires a type of CYP enzyme.
CYP enzymes are also involved in the production of bile salts which help with the digestion of fat. Intestinal problems with symptoms of fatty diarrhea can occur when there is limited bile salts available and fat soluble nutrients may be more poorly absorbed (which includes vitamin D as well as vitamin A and E).
Glyphosate was not originally developed as an herbicide it was first used medically as a mineral chelator (binds with minerals) and as an antibiotic:
It’s important to realize that glyphosate is not “just” an herbicide. As explained by Dr. Huber, it was first patented as a mineral chelator. It immobilizes nutrients, so they’re not physiologically available for your body. 
“You may have the mineral [in the plant], but if it’s chelated with glyphosate, it’s not going to be available physiologically for you to use, so you’re just eating a piece of gravel,” Dr. Huber says. 
Glyphosate is alsopatented as an antibiotic—and a very effective one at that— against a large number of beneficial organisms. Unfortunately, like all antibiotics, it also kills vitally important beneficial soil bacteria and human gut bacteria. 
“Lactobacillus, Bifidobacterium, Enterococcus faecalis—these are organisms that keep you healthy either by providing accessibility to the minerals in your food or producing many of the vitamins that you need for life. They’re also the natural biological defenses to keep Clostridium, Salmonella, and E.coli from developing in your system,” Dr. Huber explains. 
“When you take the good bacteria out, then the bad bacteria fill that void, because there aren’t any voids in nature. We have all of these gut-related problems, whether it’s autism, leaky gut, C. difficile diarrhea, gluten intolerance, or any of the other problems. All of these diseases are an expression of disruption of that intestinal microflora that keeps you healthy.” 
Glyphosate first came into use as an agricultural herbicide in the U.S. in 1974. Use of the herbicide in the U.S. increased significantly around 2005 when the use of genetically modified Round-UP Ready crops became more common. “Nearly 67 % of total agricultural glyphosate use in the U.S. since 1974 has occurred in just the last 10 years (Table 2).”  Table 3 from the same reference shows a significant increase in use of glyphosate also occurred between 1995 to 2000 but then the total use doubled again between 2000 and 2005 and has not quite doubled again between 2005 and 2014. Table 4 shows that the timing of use and increase of use is similar for global averages. And Table 5 simplifies the information by showing the amount used each decade since 1974 as a percentage of the total; 71.6% of the total agricultural use occurred in the years between 2005 and 2014. Glyphosate is also used as a spray along railroad tracks and other areas where an herbicide that kills all types of plants is desired (and frequently glyphosate used for non-agricultural purposes may be used in those areas at higher concentrations than recommended for agricultural uses or it may be sprayed more often). 
It is unethical to use humans as research test subjects for assessing the toxicity of a substance but when a substance is approved for use in the food supply then the entire population become test subjects (whether they know or not). Comparing health data between communities or countries that don’t use glyphosate products and those that do then becomes a way to assess toxicity of the substance — without having to worry about any pesky ethical issues in research design — the government says the stuff is safe so it must be safe right? The entire population where a product is in use can be assumed to be in the experimental group on average; individuals may or may not be consuming the same amounts of the substance but on average within the country or community where a product is in the use the average person may be assumed to have been exposed to an average amount that would be more than the average amount of exposure that an individual living in a country or community where the product is not in use making those individuals part of the control group — less exposed to the substance in question.
Assessing the health of populations that may be exposed to larger amounts of the suspected toxin can be another way to do “human” research without directly giving toxins to experimental test subjects in one group and not giving the toxins to the control group.
Agricultural workers might be exposed to more of an agricultural herbicide or pesticide than people who simply are eating foods that might have herbicide or pesticide residues. And sure enough agricultural workers do seem to be suffering from negative health affects due to glyphosate. Kidney failure has been a problem among sugar cane cutters and glyphosate is now used as a desiccant applied to the crop just before harvest. Kidney failure has also been observed in agricultural workers in Costa Rica and India:
“Agricultural workers in Costa Rica and India are experiencing high rate of kidney failure.” – 
Looking at the rates of increase in disease compared to the rate of increase in use of the suspected toxin can be another way to do “human” research without directly giving an experimental group toxins and not giving the toxin to the control group. When looking at the rate of disease increase there are over thirty diseases including autism and Alzheimer’s Disease with increasing rates of incidence that overlap the increased rate of glyphosate and genetically engineered proteins in our food supply:
2. Epidemiological patterns show there’s an identical rise in over 30 human diseases correlated with our increased usage of glyphosate and the increased prevalence of genetically engineered proteins in our food. 
Genetically engineered proteins refers to the mystery substances that can be created during the process of developing genetically modified organisms. Genes from one species are inserted into the DNA of the organism that is being modified. The segment of DNA that is inserted may contain many individual genes that encode a variety of proteins in addition to the desired one (such as resistance to glyphosate). New allergenic proteins can be created in addition to the desired goal (of resistance to glyphosate for example). 
Do we want a food supply based on traditional foods that nourish the body as nature designed? Or do we want a corporate profit system that sells food like substances that are actually man-made, untested experiments? Genetically modified crops have been shown to have less nutrient content and more herbicide and pesticide residue than traditional crops as well as the mystery genetically engineered proteins.
To give a gross but memorable example – what if the makers of clam tomato juice (a real product used in some alcoholic drinks) wanted to save their product from the risk of ocean acidity or increased temperatures in fresh water ecosystems  causing a reduction in the number of clams available for making clam juice and so they decided to develop a genetically modified clam flavored tomato?
The segment of DNA that encodes for clam aroma might be selected for insertion into a tomato seed’s DNA. The segment of DNA from the clam, however, might also include a few other genes that encode for shellfish proteins that cause allergies. If the genetically modified tomato incorporates not only the clam aroma gene but also incorporates some allergy causing shellfish protein genes then the resulting genetically modified clam-tomato would be an allergy risk to people with shellfish allergies.
This would not be a problem if the GM clam-tomato was only used to make clam tomato juice as consumers with shellfish allergies would have a product label that suggested there was clam content in the substance but if the GM clam tomatoes ended up being grown as a replacement for most of the tomatoes and were used in most tomato products then the shellfish allergic person might not know to start avoiding all tomato products in addition to having to avoid all shellfish products. (This is a smelly and not realistic example; if the GM hybrid worked as hoped then the clam aroma would be obvious whether the label mentioned GMO or not and so shellfish allergy sufferers would likely learn to avoid tomato products after having a few bad reactions or to at least sniff them before eating.)
I digress and am now giggling, sorry for the smelly example. Except that people with fish allergies actually may be at risk from a different type of genetically modified tomatoes:
Tomatoes have been developed that resist frost and freezing temperatures with antifreeze genes from a cold-water fish, the winter flounder (Pseudopleuronectes americanus). 
The cold-water fish-tomato GMO has not been approved yet for general use so fish allergy sufferers can eat tomato products without worry (yet, tomato isn’t on this list of GMO crops that have been approved for general use:  *and I haven’t cross checked this reference for validity, it may be a joke, I read it on the internet after all aplogies to the scientists involved if it isn’t a joke.
But do we really want a food supply based on man-made untested experiments? Or on man-made untested herbicides that may have originally been designed as mineral chelators or antibiotics? Or on man-made untested experiments that produce pesticides within the portion of the plant that is intended to be sold for human or animal consumption? (Bt GMOs are designed to produce a bacterial toxin within all parts of the plant so insects eating any part of the plant will be killed by the bacterial toxin. The GM Bt toxin turns out to be a slightly different shape than the type of Bt toxin that was traditionally used as a surface spray pesticide and which was used as a basis for safety expections about the Bt GMOs.  More on Bt crops and other references are in the last post.)
Genetic modification is not well controlled with one specific gene being inserted into the plant to by modified. A segment with many genes may be inserted and a number of changes can occur within the new species of plant. We are playing with Mother Nature or God’s roles in the creation of life. Genetic modification may be profitable for the agribusinesses or chemical company but it may be costing our environment and individual health more than we realize. Our food supply is not the only species at risk for human manipulation. Goats have been genetically modified to produce spider silk proteins within their milk which is then filtered out to be used to “make a lightweight, ultra-strong silk with a wide range of industrial and medical uses.”  *I didn’t cross check this for validity. (While that’s great for humans is it healthy for the new species baby spider-goats? *my term. The article does not mention whether baby spider-goats are allowed to nurse from their mother’s or if they are bottle fed goat milk from normal goats.)
If there’s a summary point it may be that we really need to stop the use of glyphosate and Round-Up Ready genetically modified crops and Bt crops and any others that have been associated with up to or over 30 diseases. “Proof” that something is harmful can be difficult to provide when human clinical trials can’t ethically be performed due to the risks of the experimental substance. We have to rely on the less clear but increasing large amount of circumstantial evidence that humans (and animals and insects and soil microbes) are being harmed by the man-made and largely untested experimental crops and chemical herbicides and pesticides. Agricultural workers as a group are among the most at-risk group of industrial workers for suffering acute or long-term health problems due to chemical exposure  — they are producing our “food” or are they producing our “food-like toxin delivery units“?
Lack of protective gear and safety information in a foreign language are part of the problem of farm-worker poisonings. The majority of acute (short-term high dose exposure) poisonings occur in developing nations even though the they don’t use the majority of total pesticides used globally. “As a result of the frequently problematic handling of pesticides in developing countries, 70% of all pesticide poisonings and 99% of resulting deaths occur in these countries, despite the fact that of all pesticides used globally, only 25% are applied there.” 
It’s a little unrealistic but individually if enough consumers stopped buying all of the Round-Up Ready GMO crops and crops that use it as a desiccant and Bt crops then maybe eventually the agribusiness profit margin would be affected enough to lead to their spontaneously stopping the use of those products. I won’t hold my breath though, I will just continue avoiding the products myself as I have found they do make my autoimmune symptoms worse.
This is likely an incomplete list but just for starters:
The glyphosate avoid list: “corn, soy, sugar beets, canola oil, and cottonseed oil, as well as wheat and sugar cane” (glyphosate is used as a desiccant on wheat and sugar cane) [http://www.westonaprice.org/health-topics/roundup-the-nontoxic-chemical-that-may-be-destroying-our-health/]
The Bt avoid list: corn, cotton (the cotton crop may be used to make cottonseed oil which is used in prepared deep fried foods, in margarine, and other oily packaged foods). [9, 10] *I’m not sure if this means cotton clothing should also be avoided as a source of glyphosate exposure or if it is just in reference to the cottonseed oil products.
And soy has been modified not only to be glyphosate resistant but it has also been developed to produce two types of Bt toxin. 
At least 90 percent of the soy, cotton, canola, corn and sugar beets sold in the United States have been genetically engineered. The adoption of herbicide-resistant corn, which had been slower in previous years, has accelerated, reaching 89 percent of U.S. corn acreagein 2014 and in 2015, according to the U.S. Department of Agriculture. 
Genetically modified products can be life saving, and they may even be able to help save species at risk from widespread infections (papaya was at great risk from a virus and the genetic modification made a GMO virus resistant strain of papaya), but they can also be a wild-card with unknown effects on the environment and within humans and other species. The genetically modified papaya may have risks for allergy sufferers as the virus protein that was used has similar chemical structure to a known allergen and wind is causing cross-pollination and hybridization of the virus resistant strains with organic farmer’s natural strains of papaya which can then leave them at risk of being sued by the chemical company Monsanto for use of patented crop. 
“If you control the seed, you control the food; if you control the food, you control the people.” – an old saying shared by Hawaii Co. Councilwoman Margaret Wille at a “March against Monsanto” rally. 
Hawaii has had a significant amount of herbicides and pesticides and GMO crops used on the chain of islands because the Monsanto company has been raising the GMO seeds there. Hawaii Co. councilwoman Margaret Wille also shared the concern of farmers who would like to be able to sell their crops to Japan and European countries that have banned GMO crops. If wind can cause cross-hybridization of an organic crop that not only places the farmer at risk of a lawsuit by Monsanto it also makes the crop unable to be sold to Japan or other countries that have banned GMO crops. 
There is a market for non-GMO food. Crops and soil microbes and weeds are at risk of incorporating genes from genetically modified crops into their own genetic structure through cross pollination with the GMO pollen or horizontal gene transfer. The segments of genes that are inserted into a plant to create a GMO can transfer to some other types of species such as soil microbes directly in a way somewhat similar to the way the scientist made the GMO. The gene segments were designed to invade and be incorporated into the species being modified and once they are in widespread use in nature they may be continuing to invade and be incorporated into many other life forms to create super weeds and possibly may be adding to the problem of increasing varieties of drug resistant bacteria and the more virulent viral diseases that are being spread at increased rates by mosquitoes. 
Human health and Vitamin D and hormone D are important but so is protecting the environment and all of its many life forms from mobile mutant gene segments. Humans are not Mother Nature or God and so we need to stop pretending that random genetic experiments are automatically safe for widespread use with only minimal testing.
Increased rates of over thirty diseases have been associated with the introduction of GMO crops and the increased use of glyphosate and 70% of the glyphosate has been used in just the last ten years. What are we to expect regarding chronic illness and more virulent virus and drug resistant bacteria in another ten years?
*This veered away from glyphosate’s inhibition of the CYP enzyme and vitamin D and whatever my original point might have been (that glyphosate may be inhibiting the conversion of supplemental vitamin D into the form the lab tests look for — 25 hydroxy D as well as inhibiting the activation of 25 hydroxy D into the hormone form 1, 25 dihydroxy D which is essential for many things including immune health), into a more general discussion of GMOs and the environment, but the connection is that most species have many similarities in how their bodies work. And problems in human health are going to suggest problems will be occurring in other mammals’ health — our pets, livestock and wildlife. The enzymes for vitamin and hormone D and the functions of vitamin D receptor act in the same ways across many species and types of life. Health problems are likely to show up throughout the food chain due to the glyphosate being applied on food crops and for non agricultural purposes.
It lingers in the environment and in our bodies as it’s not readily broken down. Ten years of heavy use has already led to super weeds and health problems and the approval of DDT for GMO use — we need to stop risking we don’t know what kind of consequences as more toxins add up and interact in ways we also don’t know the consequences of. GMOs are very helpful but should be tested in small isolated areas for many years before being released into general use. And the issue of horizontal gene transfer and risk of more super-weeds and more virulent or drug resistant bacteria developing is a serious one that should be considered also. Genetic modification may need to be limited for use in general — it is an ethical question facing future generations as the chemicals linger.
As individuals we can avoid using glyphosate products on our own lawns and gardens. We can also try to buy more organic choices of the foods listed above but truly avoiding all of those foods is extremely difficult as they are used as ingredients in many types of processed foods that you wouldn’t think of as corn or soy or cottonseed oil (deep fried snack foods like chips). But for people who are really sick it may be worth trying to use less of the listed foods and see if you feel better. Food is our fuel and our building blocks to repair and regrow.
/Disclaimer: Opinions are my own and the information is provided for educational purposes within the guidelines of fair use. While I am a Registered Dietitian this information is not intended to provide individual health guidance. Please see a health professional for individual health care purposes./
- Jones G, et. al., Cytochrome P450-mediated metabolism of vitamin D, J Lipid Res. 2014 Jan; 55(1): 13–31. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3927478/
- Seneff, S., Roundup (C): The Elephant in the Room, MIT CSAIL, Oct. 16, 2013, [https://people.csail.mit.edu/seneff/glyphosate/glyphosate_wellesley.pptx]
- Charles M. Benbrook, Trends in Glyphosate herbicide use in the United States and globally, Environmental Sciences Europe, Bridging Science and Regulation at the Regional and European Level 2016 28:3 (Feb. 2, 2016)
- Dr. Mercola, Toxicology Expert Speaks Out About Roundup and GMOs, (Oct. 16, 2013) http://articles.mercola.com/sites/articles/archive/2013/10/06/dr-huber-gmo-foods.aspx
- by Guy Woodward, Daniel M. Perkins, Lee E. Brown, Climate change and freshwater ecosystems: impacts across multiple levels of organization, 31 May 2010. DOI: 10.1098/rstb.2010.0055, http://rstb.royalsocietypublishing.org/content/365/1549/2093 *Interesting but unrelated to CYP enzymes or glyphosate: Increased freshwater temperature can be expected to impact species’ need for nutrients as the basal metabolic rate (BMR) is increased at higher temperatures and it also increases with larger body size. So larger species may have a difficult time increasing their foraging enough to meet their increased calorie needs as their environment becomes warmer on average.
“Essentially, because individual basal metabolic rate (BMR) is set by body size and temperature, respiratory costs will rise as BMR increases, and this will be most pronounced among larger organisms at higher temperatures (Brown et al. 2004; figure 4a).”
- Pesticides and Health Hazards: Facts and Figures, Pestizid Aktions-Netzwerk e.V PAN Germany, (2012) http://www.pan-germany.org/download/Vergift_EN-201112-web.pdf
Hawaii Co. Councilwoman Margaret Wille on bill to ban GMO on the island, https://www.youtube.com/watch?v=OY_nYv_7uI4