Skip to content

Can you have too high levels of vitamin D? The researchers themselves say that the results show there is a J shaped curve linking vitamin D levels in the blood and mortality - both too high and too low levels are linked to higher levels of mortality. From Science Daily:

High levels of vitamin D is suspected of increasing mortality rates

The level of vitamin D in our blood should neither be too high nor to low. Scientists have now shown that there is a connection between high levels of vitamin D and cardiovascular deaths.

In terms of public health, a lack of vitamin D has long been a focal point. Several studies have shown that too low levels can prove detrimental to our health. However, new research from the University of Copenhagen reveals, for the first time, that also too high levels of vitamin D in our blood is connected to an increased risk of dying from a stroke or a coronary.

"We have studied the level of vitamin D in 247,574 Danes, and so far, it constitutes the world's largest basis for this type of study. We have also analysed their mortality rate over a seven-year period after taking the initial blood sample, and in that time 16,645 patients had died. Furthermore, we have looked at the connection between their deaths and their levels of vitamin D," Professor at the Department of Clinical Medicine, Peter Schwarz explains.

The conclusion is clear: the study confirms that there is indeed a correlation between mortality rates and too low levels of vitamin D, but the new thing is that the level of vitamin D can also be too high.

"If your vitamin D level is below 50 or over 100 nanomol per litre, there is an greater connection to deaths. We have looked at what caused the death of patients, and when numbers are above 100, it appears that there is an increased risk of dying from a stroke or a coronary. In other words, levels of vitamin D should not be too low, but neither should they be too high. Levels should be somewhere in between 50 and 100 nanomol per litre, and our study indicates that 70 is the most preferable level," Peter Schwartz states.

Anecdotal evidence has been saying this for years.From Science Daily:

Keep calm, anger can trigger a heart attack!

The risk of a heart attack is 8.5 times higher in the two hours following a burst of intense anger, researchers have found after investigating the link between acute emotional triggers and high risk of severe cardiac episodes. High levels of anxiety were associated with a 9.5 fold increased risk of triggering a heart attack in the two hours after an anxiety episode.

"The data shows that the higher risk of a heart attack isn't necessarily just while you're angry -- it lasts for two hours after the outburst. In the study, 'anger' was qualified as 5 and above on a 1-7 scale, referring to 'very angry, body tense, clenching fists or teeth, ready to burst', up to 'enraged, out of control, throwing objects'. Anger below this level was not associated with increased risk. "The triggers for these burst of intense anger were associated with arguments with family members (29 per cent), argument with others (42 per cent), work anger (14 per cent) and driving anger (14 per cent)," said Dr Buckley.

"Increased risk following intense anger or anxiety is most likely due to increased heart rate, blood pressure, tightening of blood vessels and increased clotting, all associated with triggering heart attacks," he said.

The study was an investigation of consecutive patients suspected of heart attack and confirmed by angiography reports at Royal North Shore hospital. Patients confirmed with acute coronary blockage were admitted, interviewed about their activities in the 48 hours before the onset of symptoms, and usual frequencies of activities were recorded for comparison.

"Although the incidence of anger-triggered heart attacks is around 2%, of the sample, those people were 8.5 times more likely to have a heart attack within two hours of the emotional episode. So while the absolute risk of any one episode triggering a heart attack is low, this data demonstrates that the danger is very present.

Another study finding a benefit of coffee consumption - this time linked to a lower rate of MS. Keep in mind that numerous studies have shown a strong association of higher sunlight exposure (especially in childhood), and living at lower latitudes (more sunlight exposure) with lower rates of multiple sclerosis. From Science Daily:

Can coffee reduce your risk of MS?

Drinking coffee may be associated with a lower risk of developing multiple sclerosis (MS), according to a study released today that will be presented at the American Academy of Neurology's 67th Annual Meeting in Washington, DC, April 18 to 25, 2015."Caffeine intake has been associated with a reduced risk of Parkinson's and Alzheimer's diseases, and our study shows that coffee intake may also protect against MS, supporting the idea that the drug may have protective effects for the brain," said study author Ellen Mowry, MD, MCR, with Johns Hopkins University School of Medicine in Baltimore and a member of the American Academy of Neurology.

For the study, researchers looked at a Swedish study of 1,629 people with MS and 2,807 healthy people, and a U.S. study of 1,159 people with MS and 1,172 healthy people. The studies characterized coffee consumption among persons with MS one and five years before MS symptoms began (as well as 10 years before MS symptoms began in the Swedish study) and compared it to coffee consumption of people who did not have MS at similar time periods. The study also accounted for other factors such as age, sex, smoking, body mass index, and sun exposure habits.

The Swedish study found that compared to people who drank at least six cups of coffee per day during the year before symptoms appeared, those who did not drink coffee had about a one and a half times increased risk of developing MS. Drinking large amounts of coffee five or 10 years before symptoms started was similarly protective.

In the US study, people who didn't drink coffee were also about one and a half times more likely to develop the disease than those who drank four or more cups of coffee per day in the year before symptoms started to develop the disease.

It is surprising how beneficial short 30 minute naps are after sleep deprivation. From Medscape:

Napping Restores Immune System After Sleep Deprivation

Simply taking a couple of naps may counteract the impact of a sleep-restricted night on stress and immune markers, a finding that could potentially benefit night and shift workers or other chronically sleep-deprived populations, the results of a French study indicate.

Brice Faraut, PhD, from the Université Paris Descartes-Sorbonne Paris Cité, France, and colleagues found that, after a night with only 2 hours of sleep, taking two naps of just 30 minutes each appeared to normalize levels of cytokines and catecholamines.

"Napping as a countermeasure to sleep restriction could, in addition to benefits on alertness, improve neuroendocrine stress and immune recovery, with a potential prophylactic long-term effect on cardiovascular health," the researchers write.

They conducted their crossover, randomized study in which 11 healthy men aged between 25 and 32 years underwent two sessions of laboratory sleep testing in which their sleep–wake status, light environment, and caloric intake were strictly controlled.

In a "sleep-restriction" session, the participants slept for just 2 hours for one night after a baseline night of 8 hours of sleep, followed by a recovery night of sleeping. In the "sleep-restriction/nap" session, they repeated the protocol, but with two 30-minute naps after the sleep-restricted night. Salivary samples were taken every 2 hours and analyzed for interleukin (IL)-6 levels, an inflammatory cytokine known to have diurnal variations in concentration. In addition, urine samples were taken every 3 hours to measure levels of epinephrine, norepinephrine, and dopamine.

In the sleep-restricted session, there was a significant 2.5-fold increase in norepinephrine levels in the afternoon compared with the control day (P = .003). However, those differences were not seen when participants were able to take two 30-minute naps. No significant differences were seen either for epinephrine or dopamine, the researchers report.

After a sleep-restricted night, IL-6 levels were significantly lower at 10:00 am and 7:00 pm than levels measured at the same times after the control night's sleep (P = .01 and P = .05, respectively). Again, those differences were not observed when participants were able to take the two 30-minute naps.

Interestingly, daytime napping was associated with a significantly reduced amount of slow-wave sleep during the recovery night compared with sleep restriction alone (P = .01) and a trend toward decreased total sleep time."Our data suggest that napping has stress-releasing and immune effects," the researchers conclude.

Image result for dark chocolate Now this is shocking news for chocolate lovers - that it may be contaminated with lead and cadmium! Maybe it's not so bad for those who rarely eat chocolate, but it's not good for those who really love their chocolate and eat a lot. The group As You Sow did independent laboratory testing of 42 chocolate products for lead and cadmium and found that 26 of the chocolate products (~62%) contained lead and/or cadmium at levels in which one serving exceeds theCalifornia safe harbor level for reproductive harm.From The Washington Post:

How much lead is in your chocolate?

If you (like me) have been happily snarfing down chocolate in recent years, secure in the knowledge that those flavonols were at least doing good things for your heart, today is not your day. Just in time for Valentine's Day, a California consumer health watchdog group filed legal notices Wednesday demanding that many of the big chocolate companies post warnings on their packages that show their products contain high levels of lead and cadmium.

As You Sow, an Oakland nonprofit, says single servings of  26 products it tested (three times) contain more of the two harmful heavy metals than allowed under the Golden State's Proposition 65 toxic chemical warning law. Here is the list, which includes many of the big name producers of my favorite food. Try not to weep openly at work.

"We are getting [lead and cadmium] from multiple sources," Eleanne Van Vliet, director of toxic chemicals research for As You Sow, said in an interview. "The problem with those toxic heavy metals is they accumulate in the body. It’s terrible for adults, but especially for children." Overexposure to lead, of course, can cause all kinds of health problems,including lowering children's IQ. Cadmium is a carcinogen and can cause kidney and bone damage.

Now before you ask the boss to remove all the vending machines, let's be clear that the chocolate companies, and the association that represents them, are having none of this. They say there are, at worst, trace amounts of lead and cadmium in chocolate from natural sources and that regulators have rejected this argument before....Van Vliet insists that As You Sow is not talking about tiny amounts; rather, she says, if you think about the amount of chocolate the average person consumes each year, these concentrations are worrisome.If we could get them all in a room, both sides would probably agree on one thing: We do eat a lot of chocolate. 

.However, that prompted researchers at the University of California Santa Cruz to look into the amount of lead (but not cadmium) in chocolate, and the results were somewhat sobering. Their study, published in 2005 in the journal Environmental Health Perspectives, concluded that the lead in chocolate was not from naturally occurring sources, a stance that one of the researchers, Russ Flegal, reiterated when I called him.

"The average lead concentration of cocoa beans was ≤ 0.5 ng/g, which is one of the lowest reported values for a natural food," they wrote. "In contrast, lead concentrations of manufactured cocoa and chocolate products were as high as 230 and 70 ng/g, respectively, which are consistent with market-basket surveys that have repeatedly listed lead concentrations in chocolate products among the highest reported for all foods. One source of contamination of the finished products is tentatively attributed to atmospheric emissions of leaded gasoline, which is still being used in Nigeria."

Van Vliet says she doesn't know where the metals come from, only that they may enter the chocolate somewhere in the manufacturing process -- which Flegal said is also possible -- and are at unsafe levels in the chocolate we eat.

Yes, this finding is important , but what should be also noted is this sentence in the article: "He also noted that it may not be a disease itself, but the treatment for the disease, that's actually responsible for reproductive malfunction." It has been known for decades that men's sperm is affected by environmental chemicals (such as pesticides), alcohol, smoking, and medications. So it's important to figure out if it's the medicine or the health condition that's causing the problem - or perhaps it's both. From Science Daily:

Infertility is a warning: Poor semen quality linked to hypertension, other health problems

A study of men who were evaluated for the cause of their infertility finds previously unknown relationships between deficiencies in their semen and other, seemingly unrelated health problems. A study of more than 9,000 men with fertility problems has revealed a correlation between the number of different defects in a man's semen and the likelihood that the man has other health problems.

The study, conducted by investigators at the Stanford University School of Medicine, also links poor semen quality to a higher chance of having various specific health conditions, such as hypertension, and more generally to skin and endocrine disorders....A study Eisenberg co-authored a few years ago showed that infertile men had higher rates of overall mortality, as well as mortality linked to heart problems, in the years following an infertility evaluation. 

In the new study, Eisenberg and his colleagues analyzed the medical records of 9,387 men, mostly between 30 and 50 years old, who had been evaluated at Stanford Hospital & Clinics (now Stanford Health Care) between 1994 and 2011 to determine the cause of their infertility. ...So, using the database, the investigators were able to compare the overall health status of men who had semen defects to that of the men who didn't.

With a median age of 38, this was a fairly young group of men. However, 44 percent of all the men had some additional health problem besides the fertility problem that brought them to the clinic. In particular, the investigators found a substantial link between poor semen quality and specific diseases of the circulatory system, notably hypertension, vascular disease and heart disease. 

In addition, as the number of different kinds of defects in a man's semen rose, so did his likelihood of having a skin disease or endocrine disorder. When looking at the severity of all health problems, the scientists observed a statistically significant connection between the number of different ways in which a man's semen was deficient and the likelihood of his having a substantial health problem.... He also noted that it may not be a disease itself, but the treatment for the disease, that's actually responsible for reproductive malfunction. He said he is exploring this possibility now.

This article mentions a few of the other issues that are linked with male infertility.While incomplete, at least it mentions smoking, BPA exposure, binge drinking, obesity, and lack of sleep.From Medical Daily:

Your Sperm And Your Health: What Your Semen Can Tell You About Your Health

The following article focused on other links to male infertility. It also discussed an interesting 2012 study that looked at the effects of wearing tight briefs (which heats the genitals) versus boxers on sperm production (hint: briefs had very negative effect). From Five Thirty Eight Science:

Men, Those Tightie Whities Really Are Killing Your Sperm Count

Much has been written about boxing, concussions, and brain damage, but this is the first time I've read about mixed martial art fighters also having such problems. But it makes sense. From Medscape:

Fight Exposure Linked to Reduced Brain Volume

The more boxers and martial arts practitioners experience head trauma, the more likely they are to have lower brain volume, particularly caudate and thalamus volume, according to a new study. Lower brain volume in these fighters correlated with reduced processing speed, the study also found.

These results "suggest that greater exposure to head trauma is related to detectable brain structural and performance deficits in active fighters," the authors, led by Charles Bernick, MD, Lou Ruvo Center for Brain Health, Cleveland Clinic, Las Vegas, Nevada, conclude.

The analysis included 224 adults, aged 18 to 44 years, who were participants in the Professional Fighters Brain Health Study, a longitudinal cohort study of boxers and mixed martial arts (MMA) fighters. The participants included 93 boxers and 131 MMA fighters.The length of professional fighting in this group ranged from 0 to 24 years, with a mean of 4 years. The number of professional fights ranged from 0 to 101, with a mean of 10 fights.

The study also included a control group of 22 age- and education-matched participants with no history of head trauma who did not play a sport associated with head injuries from high school onward.Participants were assessed at baseline and then annually for 4 years. Researchers measured cognitive function with a computer-based battery consisting of tests of  verbal memory, processing speed, and other functions. They used MRI to assess brain volumes.

The study found that increasing exposure to head trauma, as measured by the number of professional fights or years of professional fighting, was generally associated with lower brain structural volumes, particularly subcortical structures. The most consistent relationship between exposure variables and brain volume was seen in the thalamus and caudate

The thalamus acts as a "gateway" to the cortex and when affected can influence many neurologic functions, said the authors. It and the caudate are vulnerable to volumetric loss through several mechanisms. Rotational movement of the head brought on by punches in boxing or MMA can result in diffuse axonal injury in white matter tracts, they note.

For the most part, brain structure volumes were lower for boxers than MMA fighters or controls. This could be due to several factors, the authors write. "Perhaps the most obvious explanation is that boxers get hit in the head more. In addition to trying to concuss (ie, knock out) their opponent, MMA fighters can utilise other combat skills such as wrestling and jiu jitsu to win their match by submission without causing a concussion."

The study also found that processing speed was correlated with reduced volume in several cortical and subcortical structures. Reduction in processing speed, said the authors, is consistent with repeated concussions and is considered a clinical component of chronic traumatic encephalopathy.

Essential oils - a whole new exciting area of research, with possible uses in animal and human health, and as an alternative to antibiotics. From The Atlantic:

Essential Oils Might Be the New Antibiotics

Faced with increasingly drug-resistant bacteria, scientists and farmers are now looking to plant extracts to keep people and animals healthy.

Essential oils often evoke thoughts of scented candles and day spas, but their benefits beyond relaxation are less well-known. Essential oils are ultimately just plant extracts—and those are used in countless cleaning and personal-care products, and are the main ingredient in some pest-control products and some over-the-counter medications, like Vick’s VapoRub and some lice sprays. They’re used in the food industry because of their preservative potency against food-borne pathogens—thanks to their antimicrobial, antibacterial, and antifungal properties. Various oils have also been shown to effectively treat a wide range of common health issues such as nausea and migraines, and a rapidly growing body of research is finding that they are powerful enough to kill human cancer cells of the breast, colon, mouth, skin, and more.

A handful of promising, real-life studies have been conducted with humans and other animals, though most of the research in that realm thus far has been conducted in the lab. More controlled trials will be required before some of these applications  will be available to the public, but meanwhile, scientists have turned up exciting results in another area of use: countering the growing antibiotic-resistance crisis.

As Cari Romm previously reported in The Atlantic, livestock consume up to 80 percent of the antibiotics used in the U.S., and the amount actually jumped by 16 percent between 2009 and 2012, according to a recent FDA report. This rampant use of the drugs has led to “superbugs” that are becoming increasingly resistant to the antibiotics that are used to treat not just farm animals, but humans as well. In fact, almost 70 percent of the antibiotics given to these animals are classified as “medically important” for humans...While the drugs are, of course, sometimes necessary to treat infections in livestock, the real reasons they’re overused are to speed up growth and to compensate for the cramped, unsanitary living conditions the animals endure. 

Whether farmers choose to use it or not, there is a strong alternative on the horizon. Numerous recent studies—including several done by the USDA—have shown great promise in using essential oils as an alternative to antibiotics in livestock. One of their studies, published in October 2014 in the journal Poultry Science, found that chickens who consumed feed with added oregano oil had a 59 percent lower mortality rate due to ascites, a common infection in poultry, than untreated chickens. Other research, from a 2011 issue of BMC Proceedings, showed that adding a combination of plant extracts—from oregano, cinnamon, and chili peppers—actually changed the gene expression of treated chickens, resulting in weight gain as well as protection against an injected intestinal infection.

Researchers have also directly compared the effects of commonly used antibiotics with those of various essential oils. One such study, from the March 2012 issue of the Journal of Animal Science, found that rosemary and oregano oils resulted in the same amount of growth in chickens as the antibiotic avilamycin, and that the oils killed bacteria, too. Additional findings have shown that essential oils help reduce salmonella in chickens, and another study found that a blend of several oils can limit the spread of salmonella among animals. One of the co-authors of that study, Dr. Charles Hofacre, a professor at the University of Georgia’s College of Veterinary Medicine, says it’s such a new area of research that they don’t yet know exactly how the essential oils work, but “there is some strong evidence that they are functioning by both an antibacterial action in the intestine and also some have an effect to stimulate the intestinal cells ability to recover from disease more quickly–either by local immunity or helping keep the intestinal cells themselves healthier.”

Of course, there is also a dire need for alternatives to antibiotics for the direct treatment of infections in humans and animals, not only for illness prevention and growth-boosting in livestock. Research investigating the use of essential oils in humans has produced encouraging results, but such studies have been small and surprisingly rare, especially given the demonstrated success of their use in livestock. An Italian study found that a combination of thyme and clove essential oils was just as effective in treating bacterial vaginosis as the usual antibiotic treatment, and results of a study by U.S. researchers show that staph-infected wounds healed faster when they were treated with vapors of tea-tree oil than with conventional methods. Research published in December 2013 reported that a hand gel made with lemongrass oil was effective in reducing MRSA on the skin of human volunteers...

In the lab, scientists have been testing all kinds of combinations of essential oils and antibiotics, and they’re repeatedly finding that the oils—used on their own and in combination with some common antibiotics—can fight numerous pathogens, including antibiotic-resistant strains of E. coli, Staphylococcus aureus (which causes staph infection), and other common types of bacteria. Results consistently show that combining essential oils and antibiotics significantly lowers the amount of antibiotic required to do the job. For example, two recent studies showed that lavender and cinnamon essential oils killed E. coli, and when combined with the antibiotic piperacillin, the oils reversed the resistance of the E. coli bacteria to the antibiotic. Another recent study found that basil oil and rosemary oil were both effective in inhibiting the growth of 60 strains of E. coli retrieved from hospital patients. Other research has produced similar results for many other essential oils, both alone and in combination with antibiotics. Researchers believe that one mechanism by which the oils work is by weakening the cell wall of resistant bacteria, thereby damaging or killing the cells while also allowing the antibiotic in.

Gay explains that “phytonutrients” or “phytochemicals” are chemical compounds derived from plants that have a range of health benefits, “including promoting tumor killing and increased resistance to infectious diseases, and they have been used as health-promoting agents by many cultures for several millennia.” Their potency isn’t surprising when you consider that the plant compounds that make up essential oils exist in the first place to help plants protect themselves from infection, endure temperature variations, heal from damage, and repel pests. 

Back on the farms, some are already putting essential oils into practice. “There are a number of companies that are currently selling plant extracts as feed additive, and large integrated producers are also adding feed additives to their rations to enhance the health of animals, especially their intestinal health, during their production cycle,” Gay says. No one seems willing to readily offer that information, though—and they don’t have to. One farmer who has talked publicly about using essential oils is Scott Sechler, owner of Bell & Evans Farms, a high-end producer of antibiotic-free poultry. Back in 2012, he told the New York Times about his use of oregano oil and cinnamon to fight infection on his farms, which now number about 140 with a total of 9 million chickens at any given time.

I bet eating fresh blueberries daily instead of blueberry powder would not only be more delicious, but also have even more health benefits. From Science Daily:

Blueberries may help reduce blood pressure and arterial stiffness

Just one cup of blueberries per day could be the key to reducing blood pressure and arterial stiffness, both of which are associated with cardiovascular disease. .... Johnson said she is interested in looking at how functional foods -- foods that have a positive impact on health beyond basic nutrition -- can prevent and reverse negative health outcomes, particularly for postmenopausal women.

Over an eight-week period, 48 postmenopausal women with pre- and stage-1 hypertension were randomly assigned to receive either 22 grams of freeze-dried blueberry powder -- the equivalent to one cup of fresh blueberries -- or 22 grams of a placebo powder. Participants, meanwhile, continued their normal diet and exercise routines.

At the end of the eight weeks, participants receiving the blueberry powder on average had a 7 mmHg (5.1 percent) decrease in systolic blood pressure, which is the top number in the blood pressure reading that measures the pressure in the arteries when the heart beats. They also saw a 5 mmHg (6.3 percent) reduction in diastolic blood pressure, or the bottom number measuring the pressure in the arteries between heartbeats.

Additionally, participants in the blueberry-treated group had an average reduction of 97 cm/second (6.5 percent) in arterial stiffness.They also found that nitric oxide, a blood biomarker known to be involved in the widening of blood vessels, increased by 68.5 percent. That is important, Johnson said, because arterial stiffness and the narrowing of blood vessels are both a part of hypertension. This rise in nitric oxide helps explain the reductions in blood pressure.

And the scary part is that they only tested for 32 chemicals, but there are thousands of others they didn't test for that could be lurking in the water, including pesticides used on the lawns and grounds around outdoor swimming pools. From Science Daily:

Pharmaceuticals, personal care products could taint swimming pools

A new study suggests pharmaceuticals and chemicals from personal care products end up in swimming pools, possibly interacting with chlorine to produce disinfection byproducts with unknown properties and health effects.

Chlorination is used primarily to prevent pathogenic microorganisms from growing. Previous research has shown that many constituents of urine including urea, uric acid, and amino acids, interact with chlorine to produce potentially hazardous disinfection byproducts in swimming pools. However, chemicals from pharmaceuticals and personal care products, or PPCPs, also could be interacting with chlorine, producing potentially harmful byproducts. There are literally thousands of chemicals from pharmaceuticals and personal care products that could be getting into swimming pool water.

A research group led by Ching-Hua Huang, a professor in the School of Civil and Environmental Engineering at the Georgia Institute of Technology, has developed an analytical technique that identifies and quantifies 32 pharmaceuticals and personal care products in water... Water samples were taken from indoor swimming pools in Indiana and Georgia.

Of the 32 chemicals investigated, the researchers detected three: N,N-diethyl-m-toluamide, known as DEET, the active ingredient in insect repellants; caffeine; and tri(2-chloroethyl)-phosphate (TCEP), a flame retardant.

"The other 29 could have been present at concentrations below the detection level," Blatchley said. "And because there are literally thousands of pharmaceuticals, this is just a small subset of compounds that could be present in swimming pools. The main issue is that the release of chemicals into a place like a swimming pool is completely uncontrolled and unknown. I don't want to be an alarmist. We haven't discovered anything that would be cause for alarm right now, but the bottom line is we just don't know."

Some chemicals are volatile, which means they can escape into the air to be inhaled. Others can be ingested or absorbed through the skin."Swimmers are exposed to chemicals through three different routes: You can inhale, you can ingest and it can go through your skin. So the exposure you receive in a swimming pool setting is potentially much more extensive than the exposure you would receive by just one route alone," Blatchley said.

His previous research has shown that certain airborne contaminants are created when chlorine reacts with sweat and urine in indoor swimming pools. Pharmaceuticals may get into swimming pool water from personal care products applied to the skin such as insect repellant, makeup and sunscreen. Many pharmaceuticals that are ingested are not fully metabolized by the body and are excreted in sweat and urine.

"Urine, I think, is really the primary mode of introduction," Blatchley said. "When it comes to pharmaceuticals, these are chemicals designed to be biologically active at pretty low concentrations. Birth control pills, for example, contain hormones. If those chemicals and others are present, especially in a mixture in a water sample that humans are going to be exposed to, then what are the consequences of that? That is a largely unanswered question."...The previous research suggested that about 93 percent of uric acid introduced to pools comes from human urine.