All Posts tagged studies

Languages Protect from Memory Loss

People who speak more than two languages may lower their risk of memory loss or developing other memory problems, according to a study released today that will be presented at the American Academy of Neurology’s 63rd Annual Meeting in Honolulu April 9 to April 16, 2011. “It appears speaking more than two languages has a protective effect on memory in seniors who practice foreign languages over their lifetime or at the time of the study,” said study author Magali Perquin, PhD, with the Center for Health Studies from the Public Research Center for Health (“CRP-Santé”) in Luxembourg. Perquin is helping to lead the MemoVie study which involves a consortium of partners from different hospitals and institutions.

The study involved 230 men and women with an average age of 73 who had spoken or currently spoke two to seven languages. Of the participants, 44 reported memory loss or cognitive problems; the rest of the group had no memory issues. Researchers discovered that those people who spoke four or more languages were five times less likely to develop memory loss or cognitive problems compared to those people who only spoke two languages. People who spoke three languages were three times less likely to have memory loss or cognitive problems compared to bilinguals. In addition, people who currently spoke more than two languages were also four times less likely to have memory loss or cognitive impairment. The results accounted for the age and the education of the participants.

“Further studies are needed to try to confirm these findings and determine whether the protection is limited to thinking skills related to language or if it also extends beyond that and benefits other areas of cognition,” said Perquin. The research was conducted in Luxembourg, where there is a dense population of people who speak more than two languages. The MemoVie study was supported by The National Research Fund (FNR) from Luxembourg.

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Yet another benefit of green tea

For thousands of years, the people of China, Japan, India, and Thailand have consumed green tea and used it medicinally to treat everything from headaches to heart diseases. Over the past few decades, however, research in both Asia and the West have taken place providing scientific evidence of green tea’s numerous health benefits. As a whole, studies indicate that regular consumption of green tea may slow or prevent conditions including high cholesterol, heart disease, arthritis, impaired immune disease and liver disease. In yet another recent study on the beverage’s healthful properties, published in the academic journal Phytomedicine, researchers have found evidence that enzymes in the drink may help in fighting Alzheimer’s and other forms of dementia.

Researchers at the Newcastle University have also found that the Chinese brew may also play a vital role in guarding against cancer. The Newcastle team focused on whether or not once the tea was in the digestive system if the protective properties were still as effective. “What was really exciting was that we found when green tea is digested, the resulting chemicals are actually more effective against key triggers of Alzheimer’s,” said Ed Okello, from the university’s School of Agriculture, Food and Rural Development. “The digested compounds also had anti-cancer properties, significantly slowing down the growth of tumour cells which we were using in our experiments,” Okello said.

Previous studies have shown that polyphenols, present in black and green tea, bind with the toxic compounds and protect brain cells. When ingested, the polyphenols are broken down to produce a mix of compounds and it was these the team tested in their research. According to Okello, there are many factors that together have an influence on diseases such as cancer and dementia – a good diet, plenty of exercise and a healthy lifestyle are all important. “But I think it’s fair to say that at least one cup of green tea a day may be good for you and I would certainly recommend it,” he added.

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Fruit & Veg may not help allergy

Eating more fruits and vegetables may not protect children from developing allergies, according to a large Swedish study that questions earlier hints of benefit. Fruits and vegetables are rich in antioxidants, which are thought to reduce airway inflammation. So recent studies reporting less asthma, wheezing and hay fever among children who consumed more produce appeared to make sense.

But not all research has found that link, and the studies that did may have had a surprising flaw, said Helen Rosenlund of Karolinska Institutet in Stockholm, who led the new study. She said some proteins in fruits like apples and pears resemble the pollen parts that trigger hay fever, meaning that kids might react to both. In other words, existing allergies may have caused them to eat around the produce, rather than the other way around. “This could confuse research findings,” explained Rosenlund, “falsely suggesting that diets with fewer fruits and vegetables result in more allergic disease.”

To find out if this was the case, Rosenlund and her colleagues looked at data on nearly 2,500 eight-year-olds who had participated since birth in a larger Swedish study. Based on blood tests and questionnaires filled out by parents, the researchers found that seven percent of the children had asthma. The rates of hay fever and skin rashes were more than twice as high. The average child ate between one and two servings of fruit, and between two and three servings of vegetables each day.

At first glance, some produce did seem helpful: Kids with the biggest appetite for fruit had less than two-thirds the odds of developing hay fever than those who ate the least amount. Apples, pears and carrots appeared to be particularly helpful, the researchers report in the Journal of Allergy and Clinical Immunology, but there was no such link for vegetables overall. However, it turned out that half the children with hay fever were sensitive to birch tree pollen, one of the pollens known to resemble the proteins in apples and carrots. And sure enough, after the team repeated their analysis excluding the 122 kids with food-related allergy symptoms, the hay fever link disappeared as well. “Fruits do not seem to offer protection against allergic if diet modifications are considered,” say Rosenlund.

The researchers say more studies are needed, particularly in other parts of the world that may have a different variety of allergy triggers, or allergens. And they advise those studies should not forget to look at how allergies might influence what participants eat. “Studying diet it is not so easy when it comes to the relation with allergic disease,” Rosenlund said, “because it is such a complex disease pattern.”

SOURCE: bit.ly/g3DpI7 The Journal of Allergy and Clinical Immunology, online January 10, 2011.

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Effects of Grapefruit on Diabetes

Recent studies show that grapefruit and diabetes may share a close link. Researchers concluded that naringenin found in grapefruit may increase the body's sensitivity to insulin. This research was conducted only in the laboratory, and further studies are still needed. Grapefruit and diabetes may share a close link given some recent studies suggesting that eating of the fruit can help in controlling the disease. One recent report suggests that grapefruit may become an effective part of the treatment for type 2 diabetes as it contains the antioxidant Naringenin that can break down fats and increase a person's sensitivity to insulin.

The study also concluded that grapefruit is also capable of treating abnormal levels of cholesterol, warding off metabolic syndrome and improving a person's tolerance to glucose, factors that are all associated with diabetes. The study was conducted by scientists from the Massachusetts General Hospital Center for Engineering in Medicine and Hebrew University of Jerusalem. Although more research needs to be completed, grapefruit is a safe source of vitamins for diabetics. One-half of a grapefruit contains 52 calories and 13g of carbohydrates, and the fruit has a low rating on the glycemic index, indicating a lower propensity to drive up blood sugar levels.

Research

The antioxidant Naringenin is found in grapefruit and has been largely credited for its ability in heping to treat type 2 diabetes. Naringenin is specifically noted for being able to break down fatty acids in the liver, similar to what happens when a person undergoes fasting. Yaakov Nahmias, PhD of the Hebrew University of Jerusalem reports that the results of their study indicate that Naringenin antioxidant was found to be capable of breaking down fatty acids similar to those induced by significant amounts of fasting. It does so by activating nuclear receptors, a family of proteins that can cause the liver to break down fatty acids instead of storing them.

Another study conducted by researchers at the University of Western Ontario showed that Naringenin can correct increases in triglyceride and cholesterol levels, while resisting insulin resistance and normalizing glucose metabolism. The said study showed that Naringenin genetically reprograms the liver to burn up more excess fat, instead of storing it. The said study also showed that Naringenin is able to suppress appetite and decrease food intake, which are common strategies in controlling diabetes.

The study of MGH and Hebrew University scientists also noted that Naringenin can lower bad cholesterol called vLDL while able to cure several symptoms of type 2 diabetes.

Remains Unproven

Research on grapefruit and diabetes, however, has not yet been conducted on humans, and were only done in the laboratory on the liver cells of humans and rats. Until further studies are done to confirm the effects of grapefruit in the treatment of diabetes type 2 in humans, it is still not safe to conclude that the naringenin in grapefruits can indeed cure diabetes. Further studies are still needed to establish its efficacy as well as its overall effects in the body, including the negative effects it might have.

Thus, many health experts do not encourage patients with diabetes to increase their consumption of grapefruits or increase grape juice intake, especially if they are also taking medications. There are patients prescribed with some type of drugs to lower their cholesterol level who are advised not to drink grapefruit juice as it can increase risk of side effects.

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Generational risk of diabetes

To test their hypothesis that environmental influences experienced by the father can be passed down to the next generation in the form of changed epigenetic information, Rando and colleagues fed different diets to two groups of male mice. The first group received a standard diet, while the second received a low-protein diet. To control for maternal influences, all females were fed the same, standard diet. Rando and colleagues observed that offspring of the mice fed the low-protein diet exhibited a marked increase in the genes responsible for lipid and cholesterol synthesis in comparison to offspring of the control group fed the standard diet.

These observations are consistent with epidemiological data from two well-known human studies suggesting that parental diet has an effect on the health of offspring. One of these studies, called the Överkalix Cohort Study, conducted among residents of an isolated community in the far northeast of Sweden, found that poor diet during the paternal grandfather’s adolescence increased the risk of diabetes, obesity and cardiovascular disease in second-generation offspring. However, because these studies are retrospective and involve dynamic populations, they are unable to completely account for all social and economic variables. “Our study begins to rule out the possibility that social and economic factors, or differences in the DNA sequence, may be contributing to what we’re seeing,” said Rando. “It strongly implicates epigenetic inheritance as a contributing factor to changes in gene function.”

The results also have implications for our understanding of evolutionary processes, says Hans A. Hofmann, PhD, associate professor of integrative biology at the University of Texas at Austin and a co-author of the study. “It has increasingly become clear in recent years that mothers can endow their offspring with information about the environment, for instance via early experience and maternal factors, and thus make them possibly better adapted to environmental change. Our results show that offspring can inherit such acquired characters even from a parent they have never directly interacted with, which provides a novel mechanism through which natural selection could act in the course of evolution.” Such a process was first proposed by the early evolutionist Jean-Baptiste Lamarck, but then dismissed by 20th century biologists when genetic evidence seemed to provide a sufficient explanation.

Taken together, these studies suggest that a better understanding of the environment experienced by our parents, such as diet, may be a useful clinical tool for assessing disease risk for illnesses, such as diabetes or heart disease. “We often look at a patient’s behavior and their genes to assess risk,” said Rando. “If the patient smokes, they are going to be at an increased risk for cancer. If the family has a long history of heart disease, they might carry a gene that makes them more susceptible to heart disease. But we’re more than just our genes and our behavior. Knowing what environmental factors your parents experienced is also important.”

The next step for Rando and colleagues is to explore how and why this genetic reprogramming is being transmitted from generation to generation. “We don’t know why these genes are being reprogrammed or how, precisely, that information is being passed down to the next generation,” said Rando. “It’s consistent with the idea that when parents go hungry, it’s best for offspring to hoard calories, however, it’s not clear if these changes are advantageous in the context of a low-protein diet.”

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Studies support 3 glasses of milk daily

Individuals who drink three glasses of milk a day decrease their risk of cardiovascular disease by 18 percent, according to new research published in the American Journal of Clinical Nutrition.Researchers at Wageningen University and Harvard University examined 17 studies from the United States, Europe and Japan and found no link between the consumption of regular or low fat dairy and any increased risk of heart disease, stroke or total mortality. “Milk and dairy are the most nutritious and healthy foods available and loaded with naturally occurring nutrients, such as calcium, potassium and protein, to name a few,” said Cindy Schweitzer, technical director of the Global Dairy Platform. “It's about going back to the basics; maintaining a healthy lifestyle doesn't have to be a scientific equation.”

Schweitzer said during the past three decades as research sought to understand influencers of cardiovascular disease, simplified dietary advice including consuming only low fat dairy products emerged. However, in 2010 alone, a significant amount of new research was published from all over the world, supporting the health benefits of dairy. From dispelling the myth that dairy causes heart disease, to revealing dairy's weight loss-benefits, the following is a roundup of select dairy research conducted in 2010:

  • U.S. researchers examined 21 studies that included data from nearly 350,000 and concluded that dietary intakes of saturated fats are not associated with increases in the risk of either coronary heart disease or cardiovascular disease. The study was published in the American Journal of Clinical Nutrition.
  • A study published in the American Journal of Epidemiology examined 23,366 Swedish men and revealed that intakes of calcium above the recommended daily levels may reduce the risk of mortality from heart disease and cancer by 25 percent.
  • An Australian study published in the European Journal of Clinical Nutrition concluded that overall intake of dairy products was not associated with mortality. The 16-year prospective study of 1,529 Australian adults found that people who ate the most full-fat dairy had a 69-percent lower risk of cardiovascular death than those who ate the least.
  • A Danish study published in Physiology & Behavior concluded that an inadequate calcium intake during an energy restricted weight-loss program may trigger hunger and impair compliance to the diet.
  • An Israeli study published in the American Journal of Clinical Nutrition showed that a higher dairy calcium intake is related to greater diet-induced weight loss. The study sampled more than 300 overweight men and women during two years and found those with the highest dairy calcium intake lost 38-percent more weight than those with the lowest dairy calcium intake.

The amount of dairy recommended per day varies by country and is generally based on nutrition needs and food availability. “In the US and some European countries, three servings of dairy foods are recommended daily, said Dr. Schweitzer.”

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Five portions a day saves lives

What did the research involve?

The researchers needed to obtain several sets of data to fill their model. Data for UK deaths from coronary heart disease, stroke and cancer were obtained from the Office for National Statistics, the General Register Office for Scotland and the Northern Ireland Statistics and Research Agency. Information on the population's intake of foods and nutrients was obtained from two sources: the average intake of fatty acids, fibre, and fruit and vegetables for 2005–7 was derived from the Expenditure and Food Survey, while estimates of salt intake came from the National Diet and Nutrition Survey, 2006.

The modelling also incorporated several meta-analyses of individual studies looking at diet and disease risk factors. The researchers looked at reviews that had pooled data from randomised trials, cohort studies or case-control studies, giving priority to meta-analyses of randomised trials. These different studies were combined in the model to calculate the change in risk of disease for an individual who changes his or her diet. To estimate the change in health outcomes with a change in diet at a population level, the model used the difference between current average consumption levels and recommended levels of different foods in the UK.

What were the basic results?

In a general summary of the main findings, the researchers calculated that:

About 33,000 deaths a year would be avoided if UK dietary recommendations were met. There would be a reduction in deaths from coronary heart disease of 20,800 (95% credible interval 17,845 to 24,069), a reduction of 5,876 for deaths from stroke (3,856 to 7,364) and a reduction of 6,481 for deaths from cancer (4,487 to 8,353). About 12,500 of these avoided deaths would be in people aged 75 or under. About 18,000 of the avoided deaths would be men and 15,000 would be women. More than 15,000 of the avoided deaths (nearly half the total figure) would be due to increased consumption of fruit and vegetables. Reducing average salt intake to 6g a day would avoid 7,500 deaths annually. The greatest number of deaths avoided would be in Northern Ireland and Scotland, whose populations are furthest from achieving dietary recommendations.

How did the researchers interpret the results?

The researchers say their study suggests that increasing average consumption of fruits and vegetables to five portions a day is the target likely to offer most benefit in terms of deaths avoided. They also say that reducing recommended salt levels to 3g daily and saturated fat to 3% of total energy would achieve a similar reduction in mortality.

They conclude that their calculations based on the Dietron model are robust, pointing out that their estimate of deaths avoided is lower than a previous government survey which calculated that 70,000 deaths a year could be avoided if government dietary recommendations were met. The estimates could be used in calculating the allocation of resources for interventions aimed at reducing chronic disease.

Conclusion

This well-conducted modelling study used various data sources to link consumption of different dietary components with disease risk factors (for example blood pressure, cholesterol and obesity) and subsequent mortality from coronary heart disease, stroke and cancer. The study supports previous research showing that diet plays a crucial role in health and that a diet with plenty of fruit and vegetables, fibre and low fat and salt levels can reduce the risk of chronic disease, in particular coronary heart disease. However, its predictions are made at the population level. A model such as this cannot predict individual risk, which will depend on many factors, including family history, smoking and other lifestyle habits.

It is important to note that the figures are based on the estimates and assumptions made when using a mathematical model, and not on reality. As the authors themselves note, the modelling technique they used may have led to “some degree of double counting” and that, therefore, their estimate of reduced mortalities if dietary recommendations were met is likely to be an overestimate. Also, the accuracy of the model depends to some extent on the quality of the meta-analyses that were included, and the quality of the individual studies that were pooled within these reviews in order to establish associations between diet and particular disease risk factors.

Overall, this study supports current dietary recommendations and even though it cannot predict how diet influences risk for individuals, it does indicate that keeping to dietary recommendations reduces the risk of disease.

Dietary recommendations include eating five portions of fruit and vegetables a day (about 440g) and 18g of fibre (provided by wholegrain foods and some fruit and vegetables). It is recommended that salt intake is limited to a maximum of 6g a day and that a third of total energy is provided by fats, with saturated fat comprising 10%. The researchers point out that in 2007, according to the estimated average intakes in the sources they used, none of the UK countries met these recommendations.

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Ten major advances in heart disease in 2010

The American Heart Association has compiled its annual list of the top 10 major advances in heart disease. “We have come far in the past decade, reducing heart disease deaths by more than 27 per cent,” said Ralph Sacco of the University of Miami. “But we know there is still much to be done in improving the lives of heart disease and stroke patients – and more importantly, in preventing these devastating diseases in the first place. Scientific research will help us lead the way,” said Sacco.

The highlights of the top ten advances in cardiovascular research in 2010:

1. Tailoring treatment for people with diabetes to reduce their risk of cardiovascular disease
New research from the ACCORD Study Group offered insight into specific treatments that can reduce their risk of cardiovascular disease (CVD). The first study found that aggressive blood pressure control does not reduce CVD risk in people with type 2 diabetes at high risk for CVD. In a second study, a combination therapy with a statin plus a fibrate was no better at reducing risk than a statin alone in patients with type 2 diabetes at high risk for CVD.

2. New advances for patients who aren't candidates for conventional valve surgery
Two new studies have supported evidence that Transcatheter aortic valve implantation (TAVI) can improve symptoms and outcomes – including quality of life – even over the course of several years. While there are some risks associated with TAVI, including strokes and other major cardiovascular events, the catheter-based procedure offers significant progress in this area.

3. Improving the way we reverse sudden cardiac arrest
Significant studies reported that chest compression only, or ''Hands Only CPR'' for adults by bystander lay rescuers improves survival outcome. Public awareness campaigns resulted in increased use of hands only CPR, as well as improved survival rates. While the new procedure appeared successful in adults, it is important to note that using conventional chest compressions with rescue breathing is still important for children stricken with sudden cardiac arrest.

4. More options for reducing stroke risk in atrial fibrillation
For the first time in more than 20 years there are viable alternatives to the primary prevention of stroke for patients with atrial fibrillation (AF). Warfarin (Coumadin) has long been the standard anti-clotting drug used to reduce the risk of stroke for these patients. But it carries its own complications from bleeding, and managing the dose requires regular blood tests, making it difficult to manage for both patients and doctors. Now, several new drugs have been found to work as well as warfarin – and are simpler for patients to take – offering an important advance in this field.

5. Adjusting pacing therapies can improve outcomes for heart failure patients
New studies showed that adding additional resynchronization pacing to ICD therapy could lead to improved outcomes in an expanded group of heart failure patients. In addition, new types of ICDs (defibrillators without leads, for example) can offer options that reduce some of the risks associated with traditional devices.

6. Hopeful new procedure for infants with congenital heart disease
The Pediatric Heart Network's randomized trial of Norwood shunt types in infants with single-ventricle lesions showed that the type of shunt used makes a difference in outcomes. Better transplantation-free survival at 12 months is a possibility with this new understanding of the better shunt choice for these patients. This was the first large-scale randomized trial in congenital heart surgery, offering an approach that should provide answers to other questions in the future.

7. Finding the right anti-clotting (anti-platelet) therapy
New research from the PLATO investigators has found that ticagrelor may improve outcomes and reduce adverse events better than the current standard, clopidogrel. The CURRENT-OASIS 7 Trial is exploring the optimal dosing of clopidogrel and aspirin in patient undergoing invasive surgery. These studies will help providers better understand the situations where new choices and dosages may improve results for the patient.

8. Basic science findings offer insight into future progress
Several studies this year brought the future of medicine closer to the present with new insight into emerging technologies. Findings from stem cell therapy have shown improved quality of life and survival in several early studies of patients with chronic heart failure and support the development of future cell-based therapeutics. A large animal study defined the basic mechanisms for heart muscle regeneration initiated by specific types of stem cells. The results demonstrated that these stem cells repair scarred myocardium through promotion of the generation of new heart muscle and blood vessel).

9. Using science to support healthy lifestyle behaviours
New science examining lifestyle behaviours in adults and children, with particular emphasis on physical activity and consumption pattern, show that such conditions as obesity and hypertension are positively influenced by a change in diet with decreasing sodium levels. Results from the school setting suggest that the earlier one starts to adopt healthy behaviours the better the effect on health outcomes.

10. Get With The Guidelines participation eliminates disparity gaps in care
Racial and ethnic disparities have been found in the quality of care delivered to patients with cardiovascular disease and achieving equity and addressing disparities has implications for quality, cost, risk management, and community benefit. These findings are the first to show that participating in a quality improvement program, such as Get With The Guidelines-Coronary Artery Disease, can eliminate racial and ethnic disparities of care while increasing the overall use of evidence-based care for heart attack patients.

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Low Level of “Good” Cholesterol Associated with Alzheimer’s

A low level of “good” cholesterol is a well-known risk factor for heart disease. A new study by investigators at Columbia University College of Physicians & Surgeons now suggests that a low level of good cholesterol may also raise the risk of developing Alzheimer's disease.

“Low levels of 'good' cholesterol (a.k.a. high-density lipoproteins or HDL) are very common in the United States,” says the study's lead author, Christiane Reitz, MD, PhD, assistant professor of neurology (in the Sergievsky Center and Taub Institute). “If raising HDL can lower a person's risk of developing Alzheimer's disease, that means we may be able to significantly reduce the rate of Alzheimer's disease in the population,” Reitz says, though she cautions that the finding still must be confirmed in other studies.

The study, which appears in the December issue of Archives of Neurology, is co-authored with Jose Luchsinger, MD, MPH, associate professor of medicine and epidemiology, and Richard Mayeux, MD, director of the Gertrude Sergievsky Center and Sergievsky Professor of Neurology, Psychiatry, and Epidemiology.

Previously, the relationship between HDL and Alzheimer's disease had been unclear. Some studies found an association, but others, including one of Reitz's own, found no connection. The new study, Reitz says, follows subjects for a longer period of time than previous studies, resulting in a more accurate account of the number of subjects who ultimately develop Alzheimer's.

After monitoring 1130 elderly residents of northern Manhattan for an average of four years, the researchers found a 40 percent higher incidence of Alzheimer's in residents with low HDL (less than 55 mg/dl). The reason that low HDL is associated with a higher rate of Alzheimer's isn't understood. One possibility is that it works through stroke. “We know low HDL raises the risk of stroke and that stroke is associated with Alzheimer's, so stroke may be the mediator,” Reitz says. “But there's also evidence that HDL works by itself to clear amyloid proteins [the proteins believed to cause Alzheimer's] from the brain.”

Because the study included a large number of African Americans and Hispanics, unlike previous studies that focused on whites, the finding may indicate that low HDL is linked to a high risk of Alzheimer's in many different ethnicities.

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Low Vitamin D levels common in breast cancer

More than half of women with breast cancer have low vitamin D levels, British researchers report.”Women with breast cancer should be tested for vitamin D levels and offered supplements, if necessary,” says researcher Sonia Li, MD, of the Mount Vernon Cancer Centre in Middlesex, England. The findings were presented at the San Antonio Breast Cancer Symposium.

Some studies have suggested a link between low vitamin levels and breast cancer risk and progression, but others have not, she says. No studies have proven cause and effect. Previous research suggests a biologic rationale for vitamin D putting the brakes on breast cancer development and spread, Li says. Breast cancer cells have vitamin D receptors, and when these receptors are activated by vitamin D, it triggers a series of molecular changes that can slow cell growth and cause cells to die, she says. Even if it does not have a direct effect on the tumor, vitamin D is needed to maintain the bone health of women with breast cancer, Li says. That's especially important given the increasing use of aromatase inhibitors, which carry an increased risk of bone fractures, she says.

Vitamin D is found in some foods, especially milk and fortified cereals, and is made by the body after exposure to sunlight. It is necessary for bone health.

For the study, Li and colleagues collected blood samples from 166 women with breast cancer and measured their levels of vitamin D. Of the total, 46% had vitamin D insufficiency, defined as levels between 12.5 and 50 nanomoles per liter (nmol/L) of blood. Another 6% had vitamin D deficiency, with levels lower than 12.5 nmol/L. When ethnicity was considered, vitamin D levels were lower in Asian women than in white or other women: an average of about 36 nmol/L vs. 61 nmol/L and 39 nmol/L, respectively.

The researchers theorized that vitamin D levels would be higher in the summer, when there are more daylight hours, but the study showed no association between vitamin D levels and seasons. Last month, the U.S. Institute of Medicine issued updated guidelines stating that a blood level of 50 nmol/L (or 20 nanograms/milliliter) is sufficient for 97% of people.

This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the “peer review” process, in which outside experts scrutinize the data prior to publication in a medical journal.

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