Drinking soft drinks is associated with higher blood pressure, according to a study of over 2,500 people reported this week in the journal Hypertension. High blood pressure is a major risk factor for heart disease, which is the leading cause of death worldwide. Someone with a blood pressure level in millimetres of mercury (mmHg) of 135 over 85 is twice as likely to have a heart attack or stroke as someone with a reading of 115 over 75.
The new research shows that for every extra can of soft drink consumed per day, participants on average had a higher systolic blood pressure by 1.6 mmHg and a higher diastolic blood pressure by 0.8 mmHg. This difference was statistically significant even after adjusting for factors such as weight and height. The study did not examine the mechanism that might link soft drinks with blood pressure. However, the researchers suggest that raised uric acid, which has been linked to soft drink consumption, might raise blood pressure by reducing the levels of nitric oxide, a chemical that relaxes the lining of the blood vessels.
The association between soft drinks and higher blood pressure was especially strong in people who consumed a lot of salt as well as sugar. Diet drinks were linked with lower blood pressure levels in some analyses, but the association was not consistent or strong. Professor Paul Elliott, senior author of the study, from the School of Public Health at Imperial College London, said: “It’s widely known that if you have too much salt in your diet, you’re more likely to develop high blood pressure. The results of this study suggest that people should be careful about how much sugar they consume as well.”
The researchers analysed data from 2,696 volunteers aged between 40 and 59, in eight areas of the US and two areas of the UK. On four separate occasions over a period of three weeks on average, the participants reported what they had eaten in the preceding 24 hours, as well as giving urine samples and having their blood pressure measured. The volunteers were taking part in INTERMAP, the International Study of Macronutrients, Micronutrients and Blood Pressure.
The researchers also found that people who drink more soft drinks tended to have more unhealthy diets in general. As well as consuming more sugar, those consuming more than one soft drink a day consumed more calories by 397 kilocalories per day on average, and less fibre and minerals. Those who did not consume soft drinks had a lower body mass index (BMI) on average than those who consumed more than one drink per day. “Individuals who drink a lot of sugar-sweetened beverages appear to have less healthy diets,” said Dr Ian Brown, the study’s first author, also from the School of Public Health at Imperial College London. “They are consuming empty calories without the nutritional benefits of real food. They consume less potassium, magnesium and calcium.” “This is a population study,” Dr Brown added. “It can’t say definitively that sugary drinks raise your blood pressure, but it’s one piece of the evidence in a jigsaw puzzle that needs to be completed. In the meantime, we would advise people who want to drink sugar-sweetened beverages should do so only in moderation.”
Eating a diet rich in fibre has long been known to help keep your digestive tract working properly. It’s also thought to lower the risk of heart disease, some cancers and diabetes. Now, a new study suggests it could reduce the risk of death from cardiovascular, infectious and respiratory diseases. People who ate a high-fibre diet decreased their risk of dying over a nine year period compared to those who ate less fibre, according to a new study in the Archives of Internal Medicine.
The findings are based on a diet study from the National Institutes of Health and AARP, which included 219,123 men and 168,999 women ages 50 to 71 when the study began. Researchers from the National Cancer Institute examined food surveys completed by the participants in 1995 or 1996. After nine years about 11,000 people died and researchers used national records to determine the cause.
People who ate at least 26 grams per day were 22 percent less likely to die than those who consumed the least amount of fibre — about 13 grams per day or less. Men and women who consumed diets higher in fibre also had a reduced risk of cardiovascular, infectious and respiratory diseases, the study found. Getting fibre from grains seemed to have the biggest impact, the authors write.
The study has some limitations — mainly, people who ate high-fibre diets might also have been more likely to eat healthier diets overall, attributing to their longevity. Still, the study offers more evidence that fibre is certainly good for you. Federal dietary guidelines recommend people consume at least 14 grams of fibre per 1,000 calories, so about 28 grams for an average 2,000 calorie-per-day diet. But many experts say many people don’t get enough.
The study was carried out by researchers from University of Otago Medical School, New Zealand. Funding was provided by Genesis Oncology Trust, the Dean’s Bequest Funds of the Dunedin School of Medicine, the Gisborne East Coast Cancer Research Trust and the Director’s Cancer Research Trust. The research was published in the peer-reviewed American Journal of Epidemiology. This was a case-control study in New Zealand that compared a group of adults with bowel cancer, and a group without bowel cancer, and looked at whether they drank milk at school. School milk was freely available in most schools in New Zealand until 1967 when the government programme was stopped. Many schools in the Southland region stopped free milk as long ago as 1950.
Case-control studies are appropriate for looking at whether people with and without a disease have had a particular exposure (milk in this case). The difficulty is in accounting for all potential confounding factors, particularly other health and lifestyle factors, which could be related to both diet and bowel cancer risk, for example regular childhood milk consumption could be a reflection of a ‘healthy’ diet and other healthy lifestyle behaviours that may reduce risk of cancer. In addition, when examining such a specific dietary factor – ie milk consumed in school – it is difficult to account for all possible milk or other dairy products consumed outside of school.
In this case-control study, 562 adults (aged 30 to 69) with newly diagnosed bowel cancer were identified from the New Zealand Cancer Registry in 2007. For a control group, 571 age-matched adults without cancer were randomly selected from the electoral register. All participants were mailed a questionnaire that asked about any previous illness, use of aspirin or dietary supplements in childhood, participation in school milk programmes, other childhood milk consumption, childhood diet (including other milk and dairy), smoking, alcohol consumption prior to 25 years of age, screening tests for bowel cancer, family history of cancer, education and sociodemographic characteristics. Childhood weight and height were not questioned. For school milk consumption they were specifically asked:
- Whether they drank school milk
- How many half-pint bottles they drank a week
- What age they first drank school milk
- When they stopped drinking school milk
Statistical risk associations between school milk participation and cancer were calculated. The calculations took into account several risk factors for bowel cancer risk including age, sex, ethnicity and family history.
What were the basic results?
Data on school milk consumption was available for 552 cases and 569 controls. As expected, people who started school before 1967 were more likely to have had free school milk than those who began school after 1968. Seventy-eight percent of cases participated in the school milk programme compared with 82% of controls. School milk consumption was associated with a 30% reduced risk of developing bowel cancer (odds ratio 0.70, 95% confidence interval 0.51 to 0.96).
When looking at the effect of number of bottles consumed per week they found that compared with no bottles, five bottles per week was associated with 32% significantly decreased risk, and 10 or more bottles with 61% significantly decreased risk. However, there was no significant association with one to four bottles or six to nine bottles. The researchers found a similar trend when the total school consumption of milk was compared with no consumption: 1,200-1,599 bottles was associated with 38% significantly decreased risk; 1,600-1,799 with 43% decreased risk; and 1,800 or more bottles associated with 38% significantly decreased risk. There was no significant association with fewer than 1,200 bottles. The researchers calculated that for every 100 half-pint bottles consumed at school there was a 2.1% reduction in the risk of bowel cancer. Outside of school, there was a significantly reduced risk of bowel cancer with more than 20 dairy products a week compared with none to nine dairy products a week.
The researchers conclude that their national case-control study ‘provides evidence that school milk consumption was associated with a reduction in the risk of adult colorectal cancer in New Zealand. Furthermore, a dose-dependent relation was evident’. This study has strengths in its relatively large size, its reliable and nationally representative identification of cases and controls, and its thorough data collection. However, the conclusion that school milk consumption is associated with a reduced risk of bowel cancer in adulthood must be interpreted in light of a number of considerations:
The analysis took into account established risk factors for bowel cancer including age, sex, ethnicity and family history. However, many other potential confounders were not considered, including diet, physical activity, overweight and obesity, smoking or alcohol consumption. Diet in particular has been implicated in bowel cancer risk, with diets high in saturated fat, red meat and processed foods and low in fibre, fruit and vegetables thought to increase risk. Potentially, any of these lifestyle behaviours could be confounding the relationship between school milk consumption and bowel cancer and regular childhood milk consumption could be a reflection of a ‘healthy’ diet and other healthy lifestyle behaviours that reduce risk of cancer. When looking at the effect of number of bottles consumed per week, the researchers found that, compared with no bottles, five bottles were associated with 32% significantly decreased risk and 10 or more bottles with 61% significantly decreased risk. However, there was no significant association with one to four bottles or six to nine bottles. Therefore, the trend here is not very clear. Particularly as only 16 cases and 31 controls drank 10 or more bottles a week, statistical comparison between such small numbers should be viewed with caution. With many food questionnaires there is the potential for recall bias. For example, adults may have difficulty remembering how many bottles of school milk they drank many years before. When estimating their average weekly amount, it is highly possible that this could be inaccurate or that their consumption varied slightly from week to week and year to year. Particularly when researchers were using this response and combining it with the number of weeks in the school year and their total years at school to give a total number of bottles consumed at school (figures in 100s or 1,000s), there is the possibility of being incorrectly categorised. Hence, there may be less reliability when calculating risk according to the category of total milk bottles consumed. Cancer prevalence, and particularly environmental and lifestyle risk factors for cancer, can vary between countries. These findings in New Zealand may not be represented elsewhere. Of note, the researchers acknowledge that a cohort study in the UK found the opposite: increased childhood dairy consumption was associated with increased risk of bowel cancer. Case-control studies are most appropriate for looking at rare diseases, where you would expect there to be only a small number of cases developing among a large number of people. In the case of bowel cancer, which is common, the slightly more reliable cohort design could have also been used, where children who drank milk at school and those who didn’t were followed over time to see if they developed cancer. However, such a cohort would consequently need extensive long-term follow-up.
The possible association between milk/dairy consumption, or calcium intake, in childhood, or in later years, is worthy of further study. However, from this study alone, it cannot be concluded that school milk prevents bowel cancer later in life.
Teens whose diets include lots of sugary drinks and foods show physical signs that they are at increased risk for heart disease as adults, researchers from Emory University report. Among 2,157 teens who took part in the National Health and Nutrition Examination Survey, the average amount of added sugar eaten in a day was 119 grams (476 calories), which was 21.4 percent of all the calories these teens consumed daily, the researchers noted. “We need to be aware of sugar consumption,” said lead researcher and postdoctoral fellow Jean Welsh. “It's a significant contributor of calories to our diet and there are these associations that may prove to be very negative,” she said. “Sugar-sweetened soft drinks and sodas are the major contributor of added sugar and are a major source of calories without other important nutrients.” Awareness of the negative effects of added sugar may help people, particularly teens, cut down on the amount of sugar they consume, Welsh added. “Parents and adolescents need to become aware of the amount of added sugar they are consuming and be aware that there may be some negative health implications if not now, then down the line,” she said.
The report is published in the Jan. 10 online edition of Circulation.
Welsh's team found that teens who consumed the most added sugar had 9 percent higher LDL (“bad”) cholesterol levels, and 10 percent higher triglyceride levels (another type of blood fat), compared with those who consumed the least added sugar. Teens who took in the highest amount of added sugar also had lower levels of HDL (“good”) cholesterol than those who consumed the least amount of added sugar. In addition, teens who consumed the highest amount of added sugar showed signs of insulin resistance, which can lead to diabetes and its associated risk of heart disease, the researchers found.
The American Heart Association has recommended an upper limit for added sugars intake, based on the number of calories you need. “Most American women [teens included] should consume no more than 100 calories of added sugars per day; most men, no more than 150 calories,” the association states.
One caveat to these findings is that because of the way the study was done it is not clear if added sugars caused the differing cholesterol levels, only that they are linked. In addition, the data are only for one day and may not reflect the teen's usual diet, the researchers noted. Commenting on the study, Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine, said that “this study does not prove that dietary sugar is a cardiac risk factor in this population, but it strongly suggests it.”
The paper has three important messages, he said. First, dietary sugar intake in a representative population of teenagers is nearly double the recommended level. Second, the higher the intake of sugar, the greater the signs of cardiac risk, including elevated LDL (“bad”) cholesterol and low HDL (“good”) cholesterol. Third, the apparent harms of excess sugar are greater in overweight than in lean adolescents.
“Sugar is by no means the sole dietary threat to the health of adolescents, or adults,” Katz said. “But we now have evidence it certainly counts among the important threats to both. Reducing sugar intake by adolescents, to prevent them becoming adults with diabetes or heart disease, is a legitimate priority in public health nutrition,” he said.
SOURCES: HealthDay; Jean Welsh, M.P.H., Ph.D., R.N., postdoctoral fellow, Emory University, Atlanta; David L. Katz, M.D., M.P.H., director, Prevention Research Center, Yale University School of Medicine, New Haven, Conn.; Jan. 10, 2011, Circulation, online
Even young children appear to be consuming more caffeine, so much so that caffeine could be contributing to sleep problems in primary school children, researchers found. Three-quarters of children ages 5 to 12 consumed caffeine on an average day in a survey of parents at routine clinic visits by William J. Warzak, PhD, of the University of Nebraska Medical Center in Omaha, and colleagues. The more caffeine children consumed, the fewer hours they slept on average (P=0.02), the researchers reported online in the Journal of Pediatrics, although not drawing a causal link. The average intake was two or three times higher than the 22- to 23-mg daily average reported nearly a decade ago, they noted.
Eight- to 12-year-olds in Warzak's study averaged 109 mg of caffeine — the equivalent of nearly three 12-oz cans of soda each day. But even the 52 mg of caffeine consumed by 5- to 7-year-olds on an typical day was well above the level known to have a physiologic effect on adults, the researchers noted. “There's really no role for caffeine in kids,” Marcie Schneider, MD, of the Albert Einstein College of Medicine in New York City, emphasized in commenting on the study. “We know that caffeine raises your blood pressure, raises your heart rate, and can be addictive.” Unlike older teens who are likely drinking coffee to wake up in the mornings for school, the assumption is that younger kids are getting most of their caffeine from soda, noted Schneider, who serves as a member of the American Academy of Pediatrics Committee on Nutrition.
She urged pediatricians to raise parents' awareness of the issue, perhaps as part of the yearly checkup. “We routinely ask kids what they're eating and drinking,” “It may be something that is worth pediatricians pointing out to parents that this kid does not need caffeine in their life partially because it does some things that are negative.”
Warzak's group surveyed parents of 228 children seen at an urban outpatient pediatric clinic during routine visits about the children's average daily consumption of drinks and snacks with an emphasis on caffeine-containing items. None of the children had a known sleep disorder or medical condition that might cause bedwetting. Illustrated depictions were provided to help parents accurately estimate serving sizes.
Nearly all of the caffeine intake was consumed through beverages. Few children got a meaningful amount of caffeine from food. “Caffeine's diuretic properties have encouraged behavioral health practitioners to eliminate caffeine from the diet of children with enuresis,” the researchers noted. However, they found that intake didn't correlate with the number of nights a child wet the bed (P=0.49). Overall, enuresis was actually less likely in children who consumed caffeine.
The researchers cautioned that interpretation of these results may be complicated by cultural differences in reporting children's behavioral health concerns and that their study could not draw any causal conclusions. Schneider also noted the use of parental reports and the relatively small sample as limitations. Although the findings offered no support for removing caffeine from children's diets on the basis of bedwetting, Warzak's group concluded in the paper that “given the potential effects of caffeine on childhood behavior, a screen of caffeine consumption might be beneficial when evaluating childhood behavioral health concerns.”
Source: Warzak WJ, et al “Caffeine consumption in young children” J Pediatr 2011; DOI: 10.1016/j.jpeds.2010.11.022.
Bouhlal and co workers reported that salt had an impact on intake but fat did not. They found that in general food intake increased with salt level, noting that compared with the 'normal' salt levels, a suppression of salt induced a 25 per cent decrease in green bean intake, whereas an addition of salt induced a 15 per cent increase in pasta intake. Contrarily to initial beliefs, the researchers observed no increase in food intake with increasing added sugar level. They said the findings indicate that two to three year old children's food intake may not be affected by its added sugar content.
The study data also showed that preschool children with a higher BMI score consumed more pasta when fat level was higher. The authors said this finding may confirm previous results which highlight fatter children prefer high-fat foods. The researcher said their results imply that fat and sugar addition could be avoided in foods for children without having an impact on palatability, allowing the energy density of children's diet to be limited.
“Furthermore, these findings suggest that there is no need to add salt to pasta which is consumed anyway. On the contrary, salt suppression in vegetables, whose intake is to be promoted, should be considered cautiously,” they said.
Source: British Journal of Nutrition
Published online ahead of print, doi: 10.1017/S0007114510003752
“The impact of salt, fat and sugar levels on toddler food intake”
Authors: S. Bouhlal, S. Issanchou, S. Nicklaus
The researchers analyzed data from the National Health and Nutrition Examination Survey (2003-2006) which consisted of 4,528 US adults 18 years of age or older that had no previous hypertension diagnosis. The survey asked about dietary habits and what foods and beverages that they consumed. The researchers said that those who ate 74 grams (about 2.5 cans of sugared soda) or more each day of fructose sugar, had shown an increased risk for developing hypertension. There was a 26 percent chance for these individuals to have high blood pressure reading at 135/85mmHg , a 30 percent higher risk to have high blood pressure measured at 140/90, and a 77 percent higher risk for having blood pressure measured at 160/100 mmHg. A normal blood pressure reading is under 120/80 mmHg.
The researchers point out that even though this shows a potential trigger for high blood pressure, a randomized clinical study would need to be conducted in order to prove that a low fructose diet would prevent hypertension.
Eating more olive oil could help prevent ulcerative colitis, according to a new study co-ordinated by medical researchers at the University of East Anglia (UEA).
Presented today at the Digestive Disease Week conference in New Orleans, the findings show that people with a diet rich in oleic acid – which is present in olive oil –are far less likely to develop ulcerative colitis. Oleic acid is a monounsaturated fatty acid found in olive oil, peanut oil and grapeseed oil, as well as in butter and certain margarines.
The researchers, led by Dr Andrew Hart of UEA's School of Medicine, studied more than 25,000 people aged 40-65 living in Norfolk, UK. The volunteers were recruited to the EPIC study (European Prospective Investigation into Diet and Cancer) between 1993 and 1997. The participants, none of whom had ulcerative colitis at the outset, completed detailed food diaries which were later analysed by specially trained nutritionists working in Cambridge.
By 2004, 22 participants in the study had developed ulcerative colitis and the researchers compared their diets with those who did not develop the disease. They found that those with the highest intake of oleic acid had a 90 per cent lower risk of developing the disease.
“Oleic acid seems to help prevent the development of ulcerative colitis by blocking chemicals in the bowel that aggravate the inflammation found in this illness,” said Dr Hart.
“We estimate that around half of the cases of ulcerative colitis could be prevented if larger amounts of oleic acid were consumed. Two-to-three tablespoons of olive oil per day would have a protective effect,” said Dr Hart.
Ulcerative colitis is a distressing disease affecting 120,000 people of all ages in the UK and 1 million in the US. It is characterized by inflammation of the lining of the colon or large bowel, which causes abdominal pain, diarrhoea and weight loss.
Similar work in other countries is now required to determine if these results are reproducible there, before the link can be said to be definite. If it is confirmed that oleic acid is truly protective, dietary modifications should be considered to prevent colitis. Additionally, the use of oleic acid supplements should also be assessed in the future as a possible treatment for colitis sufferers.
The lead author of the latest research, Joan Sabaté, says the study “confirms that nuts, indeed, lower cholesterol.” A professor and the chairman of the department of nutrition at Loma Linda University, in Loma Linda, Calif., Dr. Sabaté was among the group of researchers that first linked nut consumption to a lower risk of heart attack several years ago.
That finding and others led the Food and Drug Administration in 2003 to allow processors to state on labels that “eating 1.5 ounces per day of most nuts … as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease.”
Dr. Sabaté said the research indicated that for the average person, a slightly higher amount of nuts—about 2.4 ounces, or two servings—does a better job than one serving of lowering cholesterol and triglycerides, another type of fat in the blood.
Still, he said, “we do not need many to get the benefit.” One serving of almonds is about eight nuts; a serving of smaller nuts such as peanuts is about 15 to 20 nuts.
Dr. Sabaté's analysis involved nearly 600 people with high or normal blood cholesterol levels. None of the study participants were taking cholesterol-lowering medications.
The analysis compared a control group with two groups assigned to consume two different quantities of nuts.
People in one of the nut groups consumed an average of 67 grams of nuts, or about 2.4 ounces, per day.
These people had an average reduction in total blood cholesterol concentration of 5.1%, and a reduction in low-density lipoprotein, or so-called LDL or “bad” cholesterol, of 7.4%.
For the people who consumed about 1.5 ounces of nuts, total cholesterol fell by 3.2%, while “bad” cholesterol fell by 4.9%—suggesting a dose-related response.
Those who consumed about one ounce daily of nuts, total cholesterol fell by 2.8% while LDL cholesterol fell by 4.2%.
Significantly, however, the drops in cholesterol weren't seen in people considered obese—a new finding.
More studies are needed to understand why nuts are less effective at lowering blood cholesterol concentration among obese people, the researchers said.
Dr. Sabaté said the biggest improvement in blood lipid levels were seen among people who started out with higher cholesterol levels, as well as among those who consumed a “Western” diet of high-fat meats, dairy products and refined grains, compared with people consuming a “Mediterranean” diet emphasizing whole grains, lots of fruits and vegetables, fish and relatively little red meat.
“For the general population consuming a Western diet, the incorporation of nuts into their daily diet will result in greater improvement of blood lipid levels than for individuals already following a healthy Mediterranean or low-fat diet,” researchers wrote.
Of the 25 studies, about two-thirds of them involved almonds or walnuts. The other one-third of studies looked at either macadamia, pistachio, hazelnuts or peanuts. The studies didn't include pine nuts or Brazil nuts.
The study was funded by Loma Linda University in California and by the International Tree Nut Council Nutrition Research and Education Foundation, an international group that represents the tree nut industry.
The randomized, double-blind, placebo-controlled study, which was funded by The Dannon Company, Inc., involved 638 healthy children aged three to six, all of whom attended school five days a week. Parents were asked to give their child a strawberry yogurt-like drink every day. Some of the drinks contained the probiotic strain Lactobacillus casei (L. casei) and the others did not. Parents were also asked to record how many yogurt drinks their child consumed and to keep notes on their child's health.
At the end of the study, there was a 19 percent decrease in the number of common infections—e.g., ear infections, flu, diarrhea, sinusitis–among children who had consumed the yogurt drink with the probiotics than those who had the drink without the beneficial bacteria. When the researchers broke out the individual types of illness, they found that children who had the probiotic beverage had 24 percent fewer gastrointestinal infections (e.g., diarrhea, nausea, vomiting), and 18 percent fewer upper respiratory tract infections (e.g., ear, sinusitis, strep).
The reduction in infections did not, however, result in fewer days lost from school. Merenstein commented that “It is my hope that safe and tolerable ways to reduce illnesses could eventually result in fewer missed school days which means fewer work days missed by parents.”
The finding that the probiotic yogurt drink reduced infections in children, however, is significant. This joins results from other studies demonstrating benefits of probiotics in children, including one published in Pediatrics in which they reduced cold and flu symptoms, another in which they eased diarrhea, and one showing they helped prevent eczema in infants. Generally, probiotics have also been shown to benefit people who have celiac disease, irritable bowel, colitis, and possibly autism.
Georgetown University Medical Center