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Published on Leave a comment on Vitamin D and Folic Acid Levels During Pregnancy

 Two interesting studies about vitamins during pregnancy and possible effects on the child. One found that low levels of vitamin D3 is linked to behavioral issues and ADHD symptoms in preschool aged children, while the other raises the possibility of very high levels of folic acid during pregnancy linked to autism in the child. More studies are needed.

From Medscape:  Maternal Vitamin D Deficiency and Behavioral Issues in Offspring

Maternal vitamin D deficiency in early pregnancy is associated with an increased risk of behavioral issues and attention-deficit/hyperactivity disorder (ADHD)–like symptoms in preschool children, according to new data from a birth cohort study in Greece. But no association was found between maternal vitamin D deficiency and cognitive scores in the children at age 4, reported Vasiliki Daraki, MD, an endocrinologist from the University of Crete, Heraklion, Greece, who led the analysis, which was  a poster presented at the European Congress of Endocrinology 2016.

The analysis showed that maternal vitamin D levels lower than 50 nmol/L during the first trimester of pregnancy were associated with increased behavioral problems and ADHD-like symptoms among the offspring...."The lower the mother's vitamin D levels, the higher the child's hyperactivity and inattention," reported Dr Daraki.

"I think the role of vitamin D in the developing brain is in neuronal differentiation and axon development, and these are more important for behavioral problems than for cognition," Dr Daraki added.....In the future, she and her colleagues intend to measure the cognitive function and behavioral status at the age of 7 years and determine whether the results still hold at the later age.

From Medical Xpress:  A study asks: Too much folic acid a cause of autism?

For decades, pregnant women and women who may become pregnant have been advised to take folic acid to help prevent certain birth defects. But a new study suggests it may be possible to get too much of a good thing—very high levels of the vitamin in mothers' blood at the time of childbirth was linked to higher risk of their children developing autism years later. (Other research points to an opposite relationship between folic acid and autism, showing that adequate amounts of the vitamin at the time of conception can significantly reduce the risk.) 

Folate is a vitamin found in foods that is important in cell growth and development of the nervous system. A synthetic version, folic acid, is used in supplements and is used to fortify flour and cereals. Decades ago, researchers found certain levels of folic acid could prevent major birth defects of the baby's brain and spine. In the early 1990s, U.S. health officials began recommending that all women who might become pregnant should take 400 micrograms of folic acid daily. And in the late 1990s, federal regulations began mandating that folic acid be added to flour, bread and other grain products.

The new researchers followed 1,391 children who were born at Boston University Medical Center in 1998 through 2013. About 100 of them were later diagnosed with an autism spectrum disorder. The researchers went back and looked at levels of folate and vitamin B12 in the blood of the children's mothers at the time of childbirth. They found that 16 of them had very high levels of folate, and 15 had extremely high levels of vitamin B12. If both levels are extremely high, there is more than a 17-fold greater risk that a child will develop autism, the researchers said. 

Most of the moms in the study said they took multivitamins—which would include folic acid and vitamin B12—throughout their pregnancy. But the researchers say they don't know why some women had such high levels in their blood. It may be related to taking too many supplements and eating too many fortified foods. Or there could be a genetic reason that caused some women to absorb more folate than others. Or there could be a combination, they said.

Published on Leave a comment on BPA Levels in Children and ADHD?

A recent study found that school age children with higher levels of BPA in their bodies were more likely to have an ADHD (Attention Deficit Hyperactivity Disorder)  diagnosis. BPA or Bisphenol A is everywhere (in plastics, linings of cans, etc), found in varying levels in almost everyone, but at least it is eliminated fairly rapidly from the body. So trying to avoid BPA (e.g., buying and storing food in glass containers rather than cans or plastic containers) can quickly lower levels in the body. From Environmental Health News:

Hyperactivity in children linked to plastic additive, BPA

Children in the U.S. with higher levels of BPA in their bodies were more likely to have Attention-Deficit/Hyperactivity Disorder (ADHD), according to a study. The study of 460 children across the U.S. aged 8 to 15 years old found that 11 percent of those with BPA levels higher than the median level had ADHD. In contrast, 3 percent of those children with BPA levels below the median had ADHD. The research, published online last week in the Environment Research journal, adds to evidence that children’s BPA exposure may alter brain development and lead to behavior problems such as reduced attention and hyperactivity. 

The association was stronger for boys than girls, which reflects broader ADHD rates. Nationally about 10 percent of children between 5 and 17 have had an ADHD diagnoses, with boys having a much higher rate at 14 percent. By comparison about 6 percent of girls have the disorder, according to the U.S. Centers for Disease Control and Prevention.....BPA mimics estrogen hormones.The sexes use hormones differently to influence brain function.

BPA—used to make plastic hard and shatterproof and to extend the shelf life of canned food—can leach out of can linings and into the food. Studies show that just about everyone has traces of the chemical in their body—for instance, 97 percent of the children in this study had BPA in their urine. The additive has been linked to multiple health impacts in exposed babies and children—including obesity, asthma, low birth weights and genital defects.

A 2014 study on prenatal exposure to BPA found higher levels meant more behavior problems for school-age boys. Evans, lead author of that study, said prenatal exposure to chemicals is a “window of high susceptibility,” but so are the childhood years. The brain keeps developing into the 20s. Research specifically looking at ADHD and BPA exposure has been mixed, with some finding a link and some not. Most of the previous studies, however, have been on children younger than 8 years old, and ADHD and its symptoms are often realized later than that.

Animal studies show that BPA may alter the body’s dopamine—a chemical messenger that helps people think and stay alert and focused. “Dopamine systems are modulated by estrogen and BPA is a synthetic estrogen,” Froehlich said. There are also suggestions that BPA can interact with thyroid hormones—“critical in normal brain development,” Evans said.

Published on Leave a comment on Cancer Causing Chemicals Are Polluting Our Bodies

A new report released by the non-profit environmental research organization Environmental Working Group (EWG) has found that up to 420 chemicals known or likely to cause cancer have been measured in people (detected in urine, blood, hair, etc). Exposure to these carcinogens is not just from on-the-job contact with industrial chemicals, but from ordinary everyday exposure such as consumer products, food, water, air, and pesticides used in the home and lawns.

EWG compiled this inventory of known or likely carcinogens that have been measured in people by reviewing scientific literature and publicly available biomonitoring studies. Biomonitoring is the laboratory analysis of blood, urine, serum, saliva, and other body fluids to identify the amount and number of certain chemicals (such as pesticides, fire retardants, BPA, etc) present in the human body.  Thus it measures the extent to which chemical pollution is absorbed by our bodies. The CDC has a National Biomoniitoring Program. From Environmental Working Group (EWG):

Hundreds Of Cancer-Causing Chemicals Pollute Americans’ Bodies

Hundreds of cancer-causing chemicals are building up in the bodies of Americans, according to the first comprehensive inventory of the carcinogens that have been measured in people. EWG released the inventory today. EWG spent almost a year reviewing more than 1,000 biomonitoring studies and other research by leading government agencies and independent scientists in the U.S. and around the world. The nonprofit research group found that up to 420 chemicals known or likely to cause cancer have been detected in blood, urine, hair and other human samples.

Studies of the causes of cancer often focus on tobacco, alcohol and over-exposure to the sun. But the World Health Organization and many other scientists believe nearly 1 in 5 cancers are caused by chemicals and other environmental exposures––not only in the workplaces, but in consumer products, food, water and air.

EWG’s review bolsters the findings and ongoing research of the Halifax Project, a collaboration of more than 300 scientists from around the world who are investigating new ways in which combinations of toxic chemicals in our environment may cause cancer. While most cancer research focuses on treatment, the Halifax Project and EWG’s Rethinking Cancer initiative are looking at prevention by reducing people’s contact with cancer-causing chemicals.

“The presence of a toxic chemical in our bodies does not necessarily mean it will cause harm, but this report details the astounding number of carcinogens we are exposed to in almost every part of life that are building up in our systems,” said Curt DellaValle, author of the report and a senior scientist at EWG. “At any given time some people may harbor dozens or hundreds of cancer-causing chemicals. This troubling truth underscores the need for greater awareness of our everyday exposure to chemicals and how to avoid them.”

EWG estimated that a small subset of the chemicals inventoried in the report were measured at levels high enough to pose significant cancer risks in most Americans ––risks that generally exceed Environmental Protection Agency safety standards. But those estimates are only for individual chemicals and do not account for a question scientists and doctors are increasingly concerned about––how combined exposures to multiple chemicals may increase risk?

EWG’s inventory comes at an auspicious moment for the issue of cancer and chemicals. Last week Congress passed the first reform in 40 years of the nation’s woefully weak toxic chemical regulations, which President Obama is expected to sign soon....“Many of the carcinogens this study documents in people find their way into our bodies through food, air, water and consumer products every day. Dozens of them show up in human umbilical cord blood—which means Americans are exposed to carcinogens before they’ve left the womb,” said EWG President Ken Cook. “We should focus on preventing cancer by preventing human exposure to these chemicals.”

Published on Leave a comment on Eating Whole Grains Linked To Living Longer

A second study was just published about the benefits of eating whole grains daily - again a significantly lower risk of premature death, and again the effects were dose-related. That is, the more whole grains eaten daily, the lower the risk of early death. Like the first study, this also was a review study. This study (published in BMJ) found that whole grain consumption was associated with a reduction in the risk for death from cancer, coronary heart disease (heart attack and stroke), respiratory disease, infectious disease, and diabetes.

A slice of 100 percent whole grain bread contains about 16 grams of whole grains, and current U.S. dietary guidelines recommend 48 grams or more of whole grains daily, but this study suggests that eating even more whole grains daily is best (eating 90 grams of whole grains a day reduced the risk for mortality from all causes by 17 percent).

Grains are divided into two subgroups: whole grains and refined grains. Whole grains or foods made from them contain all the essential parts and naturally-occurring nutrients of the entire grain seed in their original proportions. This definition means that 100% of the original kernel – all of the bran, germ, and endosperm – must be present to qualify as a whole grain. Some whole grains are: whole wheat. barley. buckwheat, corn (including whole cornmeal and popcorn), millet, oats (including oatmeal), quinoa, brown rice, rye, sorghum, spelt, bulgur, and wild rice. From Eurekalert:

Seven servings of whole grains a day keep the doctor away

Eating three more portions of dietary fiber a day--say, two pieces of whole grain bread and a bowl of whole grain breakfast cereal--is associated with a lower risk for all cardiovascular diseases and for dying of cancer, diabetes, and respiratory and infectious diseases, a study just published in the BMJ has shown. The study is strong proof that consuming lots of whole grains is good for our health, says first author Dagfinn Aune, a PhD candidate at the Norwegian University of Science and Technology who is currently working at Imperial College, London.

....In general, the study showed that the higher the consumption, the better protected you are. "We saw the lowest risk among people who ate between seven and seven and a half servings of whole grain products a day, which was the highest intake across all the studies. This corresponds to 210-225 grams of whole grain products in fresh weight and about 70-75 grams of whole grains in dry weight, and is about the same as the health authorities in Norway and other Nordic countries recommend as the minimum daily allowance," says Aune.

The researchers' analyses showed fewer risk factors for people who consumed more bread and cereal with whole grains, as well as foods with added bran. On the other hand, people who ate a lot of white bread, rice or cereals with refined grains did not show reduced risk.

Nine studies with a total of more than 700,000 participants examined the risk for all types of cardiovascular disease and correlated cardiovascular deaths....The risk of dying prematurely from all causes was 18% lower for individuals who consumed a lot of whole grains compared to those who consumed lesser amounts, while three additional servings each day were associated with a 17% reduction in mortality. The risk for deaths associated with cancer (15%), respiratory diseases (22%), diabetes (51%) and infectious diseases (26%) was also lower the more whole grains individuals consumed.

Published on Leave a comment on Whole Grains Are Very Good For You

Eating whole grains is good - lower death rate, fewer cardiovascular disease related deaths, fewer cancer deaths! And recent research (a review of studies) showed that the more whole grains consumed, the lower the death rate. Current dietary guidelines suggest 3 servings a day. Whole grains include: whole wheat, barley, buckwheat, millet, oats, quinoa, brown rice, rye, bulgur, spelt,and wild rice. Whole grains provide many nutrients, such as fiber, B vitamins, and minerals. From Medical Xpress:

Eating more whole grains linked with lower mortality rates

Eating at least three servings of whole grains every day could lower your risk of death, according to new research in the American Heart Association's journal Circulation. Although dietary guidelines around the world have included whole grains as an essential component of healthy eating patterns, people aren't eating enough, according to the analysis. In the United States average consumption remains below one serving a day, despite the long-time recommendation of three servings a day.

In the first meta-analysis review of studies reporting associations between whole grain consumption and death, researchers noted that for about every serving (16 grams) of whole grains there was a: 7 percent decreased risk in total deaths; 9 percent decline in cardiovascular disease-related deaths; and 5 percent decline in cancer-related deaths.

The more whole grains consumed, the lower the death rate. According to researchers, when three servings (48 grams) were consumed daily the rates declined: 20 percent for total deaths; 25 percent for cardiovascular deaths; and 14 percent for cancer-related deaths.

"Previous studies have suggested an association with consumption of whole grains and reduced risk of developing a multitude of chronic diseases that are among the top causes of deaths, although data linking whole grain intake and mortality were less consistent," said Qi Sun, M.D., Sc.D., senior author of the study and assistant professor at the Harvard T.H. Chan School of Public Health in Boston, Massachusetts. "These findings lend further support to the U.S. government's current Dietary Guidelines for Americans, which suggest higher consumption of whole grains to facilitate disease prevention."

Whole grains, such as whole wheat, oats and brown rice, contain dietary fiber, which may help improve blood cholesterol levels, and lower the risk of heart disease, stroke, obesity and type 2 diabetes. Dietary fiber can also make you feel full longer, so you may eat fewer calories.

This analysis included 12 studies published through February 2016 and unpublished results from the National Health and Nutrition Examination Survey (NHANES) III, conducted from 1988 to 1994, and NHANES 1999-2004. Of the reviewed studies, 10 were conducted in U.S. populations, three in Scandinavian countries and one in the United Kingdom. The combined studies involved 786,076 men and women with 97,867 total deaths, 23,597 deaths from cardiovascular disease, and 37,492 deaths from cancer.

Published on Leave a comment on Should a Healthy Plant-based Diet Include Lots of Sweets?

A plant-based diet (eating lots of plant foods - fruits, vegetables, whole grains, legumes, seeds and nuts) once again shows health benefits in a new study - here a lower incidence of type 2 diabetes. But what kind of plant-based foods one eats is important: consumption of a plant-based diet that emphasized healthy plant foods was associated with a larger decrease (34%) in diabetes risk, while consumption of a plant-based diet high in less healthy plant foods (soda, fruit juices, sweets/desserts, refined grains) was associated with a 16% increased diabetes risk. From Medical Xpress:

Healthy plant-based diet linked with substantially lower type 2 diabetes risk

Consuming a plant-based diet—especially one rich in high-quality plant foods such as whole grains, fruits, vegetables, nuts, and legumes—is linked with substantially lower risk of developing type 2 diabetes, according to a new study from Harvard T.H. Chan School of Public Health.

While previous studies have found links between vegetarian diets and improved health outcomes, including reduced risk of type 2 diabetes, this new study is the first to make distinctions between healthy plant-based diets and less healthy ones that include things like sweetened foods and beverages, which may be detrimental for health. The study also considered the effect of including some animal foods in the diet.

The researchers followed more than 200,000 male and female health professionals across the U.S. for more than 20 years who had regularly filled out questionnaires on their diet, lifestyle, medical history, and new disease diagnoses as part of three large long-term studies. The researchers evaluated participants' diets using a plant-based diet index in which they assigned plant-derived foods higher scores and animal-derived foods lower scores.

The study found that high adherence to a plant-based diet that was low in animal foods was associated with a 20% reduced risk of type 2 diabetes compared with low adherence to such a diet. Eating a healthy version of a plant-based diet was linked with a 34% lower diabetes risk, while a less healthy version—including foods such as refined grains, potatoes, and sugar-sweetened beverages—was linked with a 16% increased risk. Even modestly lowering animal food consumption—for example, from 5-6 servings per day to about 4 servings per day—was linked with lower diabetes incidence, the study found.

The researchers suggested that healthful plant-based diets could be lowering type 2 diabetes risk because such diets are high in fiber, antioxidants, unsaturated fatty acids, and micronutrients such as magnesium, and are low in saturated fat. Healthy plant foods may also be contributing to a healthy gut microbiome, the authors said.

Published on Leave a comment on Regular Physical Activity Is A Magic Bullet In Preventing Health Problems

A recent editorial in the journal Cardiology calls exercise the "magic bullet" in preventing all sorts of diseases, including cardiovascular disease and diabetes.

From Science Daily: Regular physical activity is 'magic bullet' for pandemics of obesity, cardiovascular disease

In an editorial published in the current issue of Cardiology, professors from the Charles E. Schmidt College of Medicine at Florida Atlantic University have evaluated the totality of evidence and conclude that regular physical activity bears the closest resemblance to a "magic bullet" to combat the worldwide epidemic of obesity and cardiovascular disease.

The statistics on regular physical activity in the United States are bleak; only about 20 percent of Americans (23 percent of men and 18 percent of women) engage in recommended levels of regular physical activity and about 64 percent never do any physical activity. In Europe, the statistics are not much better with only 33 percent who engage in physical activity with some regularity, while 42 percent never do any physical activity.

The authors also point out that physical activity confers important beneficial effects beyond body weight and include blood pressure, cholesterol, triglyceride, diabetes, heart attacks, strokes, colon cancer and possibly even breast and prostate cancers as well as arthritis, mood, energy, sleep and sex life.

Starting in their 30s, Americans and many Europeans tend to gain between 1 and 3 pounds of body weight per year, and by 55, many are between 30 and 50 pounds overweight....The authors note that brisk walking for only 20 minutes a day burns about 700 calories a week, results in a 30 to 40 percent reduced risk of coronary heart disease, and can be performed even by the elderly. They stress that regular physical activity also should include resistance exercise such as lifting weights, which can even be safely performed in the elderly and in patients with heart failure.

Published on Leave a comment on Exercise Now to Protect Your Brain Decades From Now

Get out there and start getting active NOW - the earlier you start in life, the better for your brain decades later. All physical activity or exercise is good, including regular walks. From Medical Xpress:

Regular exercise protects against cognitive decline in later years

Regular exercise in middle age is the best lifestyle change a person can make to prevent cognitive decline in the later years, a landmark 20-year study has found.

University of Melbourne researchers followed 387 Australian women from the Women's Healthy Ageing Project for two decades. The women were aged 45 to 55-years-old when the study began in 1992. The research team made note of their lifestyle factors, including exercise and diet, education, marital and employment status, number of children, mood, physical activity and smoking....They were also asked to learn a list of 10 unrelated words and attempt to recall them half an hour later, known as an Episodic Verbal Memory test.

When measuring the amount of memory loss over 20 years, frequent physical activity, normal blood pressure and high good cholesterol were all strongly associated with better recall of the words. Study author Associate Professor Cassandra Szoeke, who leads the Women's Healthy Ageing Project, said once dementia occurs, it is irreversible. "In our study more weekly exercise was associated with better memory." 

"We now know that brain changes associated with dementia take 20 to 30 years to develop," Associate Professor Szoeke said. "The evolution of cognitive decline is slow and steady, so we needed to study people over a long time period. We used a verbal memory test because that's one of the first things to decline when you develop Alzheimer's Disease."
Regular exercise of any type, from walking the dog to mountain climbing, emerged as the number one protective factor against memory loss. Asoc Prof Szoeke said that the best effects came from cumulative exercise, that is, how much you do and how often over the course of your life.  (Original study)

Published on Leave a comment on High Obesity Rates in US and Globally

Obesity rates in the US are high! Obesity rates in the US were 35% among men and 40.4% in women in 2013-2014, and extreme obesity (class 3) rates were 5.5% for men and 9.9% for women. Obesity is defined as a body mass index (BMI) 30 or greater (≥30), and extreme obesity or class 3 obesity is a body mass index of 40 or greater (BMI ≥40).

A second study analyzed data from 186 countries and found that global obesity numbers have shot up from 105 million people in 1975 to 641 million in 2014. The senior author Dr. Majid Ezzati of the study said: "Over the past 40 years, we have changed from a world in which underweight prevalence was more than double that of obesity, to one in which more people are obese than underweight."

From Science Daily: Prevalence of obesity in U.S. increases among women, but not men

The prevalence of obesity in 2013- 2014 was 35 percent among men and 40 percent among women, and between 2005 and 2014, there was an increase in prevalence among women, but not men, according to a study appearing in the June 7 issue of JAMA. Between 1980 and 2000, the prevalence of obesity increased significantly among adult men and women in the United States...The analysis included data from 2,638 adult men (average age, 47 years) and 2,817 women (average age, 48 years) from the most recent 2 years (2013-2014) of NHANES and data from 21,013 participants in previous NHANES surveys from 2005 through 2012.

For the years 2013-2014, the overall age-adjusted prevalence of obesity (body mass index [BMI] 30 or greater) was 38 percent; among men, it was 35 percent; and among women, it was 40 percent. The corresponding prevalence of class 3 (BMI 40 or greater) obesity overall was 7.7 percent; among men, it was 5.5 percent; and among women, it was 9.9 percent. 

The authors write that although there has been considerable speculation about the causes of the increases in obesity prevalence, data are lacking to show the causes of these trends, and there are few data to indicate reasons that these trends might accelerate, stop, or slow. "Other studies are needed to determine the reasons for these trends." 

From Medscape: Obesity Now More Common Than Underweight Worldwide

Global obesity numbers have shot up from 105 million people in 1975 to 641 million in 2014, according to the most comprehensive body mass index (BMI) trend analysis to date. Researchers estimate that the age-corrected proportion of men who were obese climbed from 3.2% to 10.8% in that time and the rate among women more than doubled, going from 6.4% to 14.9%. During the same 40-year period, the proportion of men who were underweight globally fell from 13.8% to 8.8% and among women it declined from 14.6% to 9.7%.

Underweight numbers were highest in South Asia in 2014 at 23.4% (95% CI, 17.8%–29.2%) in men and 24% (95% CI, 18.9%–29.3%) in women. Underweight prevalence also stood at more than 12% in women and more than 15% in men in Central and East Africa in 2014, despite some reductions over the 4 decades....Almost half of the world's underweight men (46.2%) and women (41.6%) live in India, the study found.

Polynesia and Micronesia had the highest average BMI in the world. More than 38% of men and over half of women are obese there. The study finds that almost 20% of the world's obese adults (118 million) live in six high-income countries—Australia, Canada, Ireland, New Zealand, the United Kingdom, and the United States. More than a quarter (27.1% or 50 million) of the world's severely obese people also live in these countries. More than one in four severely obese men (27.8%) and 18.3% of severely obese women in the world live in the United States.

Published on Leave a comment on Maybe Daily Meat Consumption Is Not So Bad

Surprising results (to me at least) from research comparing various diets and incidence of several cancers in 11,082 individuals in the Netherlands over a 20 year period. I expected the daily meat eaters to have higher rates of the 3 cancers studied, but no....

According to this study, looks like frequent meat consumption is OK when looking at lung, postmenopausal breast, and prostate cancer. Meat consumption did not increase the risk for these cancers.

Their main conclusion: vegetarians, pescatarians (eats fish, but no meat), and low-meat consumers did not have a reduced risk of lung, postmenopausal breast, and overall prostate cancer when compared with individuals consuming meat on a daily basis. This is after taking confounders such as smoking into account (because smokers have higher rates of cancers such as lung cancer).

The researchers do point out that some other similar studies had mixed results, but that perhaps those studies did not take confounders (variables that distort the results) such as smoking, physical activity levels, alcohol consumption, etc. into account.

From the European Journal of Clinical Nutrition: Vegetarianism, low meat consumption and the risk of lung, postmenopausal breast and prostate cancer in a population-based cohort study

The few prospective studies that examined lung, female breast and prostate cancer risk in vegetarians have yielded mixed results, whereas none have studied the effects of low meat diets. ... The Netherlands Cohort Study—Meat Investigation Cohort (NLCS-MIC)— is an analytical cohort of 11,082 individuals including 1133 self-reported vegetarians (aged 55–69 years at baseline). At baseline (1986), subjects completed a questionnaire on dietary habits and other risk factors for cancer and were classified into vegetarians (n=691), pescetarians (n=389), 1 day per week (n=1388), 2–5 days per week (n=2965) and 6–7 days per week meat consumers (n=5649).

After 20.3 years of follow-up, 279 lung, 312 postmenopausal breast and 399 prostate cancer cases (including 136 advanced) were available for analyses. After adjustment for confounding variables, we found no statistically significant association between meat consumption groups and the risk of lung cancer. As well, no significant associations were observed for postmenopausal breast and overall prostate cancer. After adjustment for confounders, individuals consuming meat 1 day per week were at a 75% increased risk of advanced prostate cancer compared with 6–7 days per week meat consumers.

Vegetarians, pescetarians and 1 day per week meat consumers did not have a reduced risk of lung, postmenopausal breast and overall prostate cancer compared with individuals consuming meat on a daily basis after taking confounders into account.

Although vegetarian diets are primarily defined by the absence of meat and fish, they are also shown to be associated with high intakes of fruits and vegetables and a favorable distribution of non-dietary factors.1, 2 Consequently, vegetarian diets may reduce the risk of different types of cancers through multiple mechanisms, depending on the etiology and preventability of the tumor.3, 4

We previously reported a nonsignificantly reduced risk of vegetarian and low meat diets on colorectal, and especially rectal, cancer5 and set out to study its effect on three other major cancers.

Although meat consumption has been hypothesized to be implicated in the etiology of lung, female breast and prostate cancer, data are not consistent across studies and meat subtypes.6, 7, 8However, on the basis of the existing body of literature, vegetarians may be at a lower risk of developing lung cancer (because of lower smoking rates) and to postmenopausal breast cancer (because of lower alcohol consumption, lower body mass index and higher physical activity levels).

Results from this prospective cohort study showed that, in age- and sex-adjusted models, vegetarians and pescetarians were at a reduced risk of lung cancer compared with individuals consuming meat on a daily basis. This effect disappeared after taking confounders, especially smoking, into account. We did not observe an association between the meat consumption group and the risk of post-menopausal breast and overall prostate cancer.

Our null findings regarding post-menopausal breast cancer risk are in line with other prospective studies comparing vegetarians with non-vegetarians and a pooled analysis of five cohort studies on breast cancer mortality. In contrast, the UK Women’s Cohort Study reported a lower post-menopausal breast cancer risk among non-meat consumers compared with high meat consumers,14 although this was not observed in their dietary pattern analyses.15 Vegetarian diets are rich in fiber and soy. Fiber was associated with a reduced risk of breast cancer in a meta-analysis of prospective studies,19 and soy contains isoflavones, which have previously been associated with a significant reduced risk of postmenopausal breast cancer in Asian populations.20 However, compared with the average soy intake in four Asian countries (ranging from 38 to 134 g/day21), the soy product intake among vegetarians in our population was likely too low to exert an effect (~15 g per day).