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Older Americans Living Longer, But Becoming More Obese PDF Print E-mail
Title: Older Americans Living Longer, But Becoming More Obese
Category: Health News
Created: 8/16/2012 6:06:00 PM
Last Editorial Review: 8/17/2012 12:00:00 AM
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Mediterranean diet link to stronger bones PDF Print E-mail

"Just two years of eating like the Spanish and Italians who use olive oil rather than less healthy fats may preserve or even build bone in older people," the Daily Mail reports.

The story is based on a study of whether the so-called Mediterranean diet – a diet rich in fresh fruit, vegetables, fish and olive oil – could strengthen bones and protect against osteoporosis.

The researchers were comparing the long-term effects of three different types of diet on blood levels of osteocalcin. Osteocalcin is a protein involved in the development of new bone.

In the study, three types of diet were assigned to older men, with an average age of 68. The three diets were:

  • a Mediterranean diet enriched with virgin olive oil
  • a Mediterranean diet enriched with nuts
  • a low fat control diet

Researchers found that in men assigned to a Mediterranean diet enriched with virgin olive oil, levels of osteocalcin and other markers for healthier bone formation were significantly higher at the end of the study’s two-year period than they were at the start. In men on the other two diets levels of these markers were not significantly different after two years.

The results of this study are of interest, especially in the light of earlier research suggesting that southern Mediterranean countries have lower levels of osteoporosis than countries in northern Europe. It may well be the case that high consumption of olive oil is associated with increased production of osteocalcin, which has a protective effect on bone. However, this is still a theory and not proven by this study.

To investigate this issue further, research that measures the effects of diet on bone strength (density) directly is required. 

 

Where did the story come from?

The study was carried out by researchers from various institutions in Spain. The lead author is based at the Hospital Dr Josep Trueta in Girona. It was partly funded by grants from the Spanish government. The study was published in the peer-reviewed Journal of Clinical Endocrinology and Metabolism.

Its findings were overstated by the Mail’s claim that swapping to a Mediterranean diet rich in olive oil “for just two years” could help protect bones in later life. While the study did find that men in the olive oil group had higher levels of the osteocalcin protein, there is, as yet, no conclusive proof that this will lead to protection against osteoporosis.

 

What kind of research was this?

This was a randomised controlled trial (RCT) comparing the effects of three different types of diets on blood levels of a marker called osteocalcin, as well as other compounds, in a group of older men.

The three diets under investigation were:

  • a Mediterranean diet enriched with virgin olive oil 
  • a Mediterranean diet enriched with nuts 
  • a low fat control diet

The authors point out that nutritional factors are known to be involved in age-related bone loss and that studies have shown the incidence of osteoporosis to be lower in the Mediterranean basin. 

Animal studies have suggested, they say, that consumption of olives and olive oil can prevent loss of bone mass. Laboratory studies have also indicated that oleuropein, a constituent of virgin olive oil, may have a protective effect, as well as being involved in the regulation of glucose in the blood.

However, there have been few, if any, studies looking at the effects of olive oil on blood levels of markers associated with formation of new bone in humans.

 

What did the research involve?

Participants in the study were 127 men, aged 55 to 80, who were randomly selected from a larger trial looking at the possible role of the Mediterranean diet in the prevention of cardiovascular disease.

The men had either been diagnosed with type 2 diabetes or they had at least three risk factors for cardiovascular disease, such as:

  • high blood pressure
  • high cholesterol levels
  • being overweight or obese
  • a family history of premature cardiovascular disease

There were several exclusion criteria for the trial including the use of medications known to affect bone formation or calcium levels.

The men were randomly assigned to three groups:

  • one group was advised to use the Mediterranean diet supplemented with virgin olive oil 
  • one group was advised to use the Mediterranean diet supplemented with mixed nuts 
  • a control group was advised to go on a low fat diet

All participants were given the same personalised dietary advice by a dietitian. The dietitian recommended:

  • the use of olive oil in cooking and dressing food
  • increased consumption of fruit, veg, pulses and fish
  • the replacement of red and processed meat with white meat
  • the avoidance of butter and cream

In addition

  • Those on the low fat diet were advised to reduce all types of fat from both animal and vegetable sources.
  • Those on the Mediterranean diet with olive oil were advised to replace refined olive oil or other vegetable oils with extra virgin olive oil, which the authors say retains certain natural phytochemicals and antioxidant compounds. The advice was to consume at least 50ml of virgin olive oil daily.
  • Those on the Mediterranean diet with nuts were allotted 30g of walnuts, almonds and hazelnuts daily.

Participants were given a short questionnaire about lifestyles, medical conditions and medication use at the start of the study and at one and two years’ follow-up. A validated food questionnaire was also used yearly to assess their dietary intake and a questionnaire was used to measure physical activity.

At the start of the study and after two years, researchers took blood samples from the men and measured levels of osteocalcin and P1NP, which are both markers for the formation of new bone. They also measured blood levels of a marker known as CTX, which is involved in the resorption of old bone. Bone resorption is a process in which older bone cells are broken down in order to release calcium to make new bone cells.

Other markers were used to measure the men’s insulin resistance, which is an indication of their risk of diabetes.

 

What were the basic results?

Researchers report that at the start of the study, the markers for bone formation were similar in all groups, as were other characteristics such as age, BMI and cholesterol levels. But after two years:

  • the total osteocalcin levels had increased significantly in the group on a Mediterranean diet with olive oil but not in the other two groups
  • P1NP also increased significantly in the group on a Mediterranean diet with olive oil but not in the other two groups
  • calcium levels decreased significantly in those on a Mediterranean diet with nuts and the low fat group but not in those on the Mediterranean diet with olive oil 
  • overall, consumption of olives had a positive association with osteocalcin levels both at the start of the study and after two years
  • the marker for bone resorption, CTX, decreased significantly in all study groups – which presumably was due to the natural effects of ageing on bone strength

 

How did the researchers interpret the results?

The researchers say that consumption of a Mediterranean diet enriched with virgin olive oil for two years is associated with increased levels of two markers for bone formation, which suggests this diet has a protective effect on bone.

 

Conclusion

This was a well conducted study and the results are of interest. Its strengths include its randomisation of participants to different groups and its relatively lengthy follow-up period. However, the study also has limitations.

The most important of these is that it did not measure the men’s bone density or fracture rate, only certain “surrogate” or intermediate blood markers associated with bone turnover, so it cannot show that a particular type of diet protects against bone loss.

In addition, the participants were originally recruited for the PREDIMED study, to look at the impact of diet on risk of diabetes or heart disease.

People recruited to the PREDIMED study were older men with pre-existing risk factors for diabetes or heart disease. So the results of this study may not apply to other populations, such as younger people or women.

It is also possible that the men did not always stick to the dietary advice given, nor accurately recall their dietary intakes over each year, which may affect the reliability of the study results. 

The Mediterranean diet has proven health benefits but, as yet, we do not know if it protects against osteoporosis, a complex condition involving not only diet but also genetic susceptibility, hormones and other lifestyle factors such as physical activity. To find out if the Mediterranean diet, with or without virgin olive oil, protects against bone loss, a long-term randomised controlled trial recruiting a wider age range of men and women for this sole purpose is required. It should measure not only bone density but also the incidence of fracture.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.

Links To The Headlines

Just two years on Mediterranean diet in mid-life could protect your bones in old age. Daily Mail. August 16 2012

Links To Science

Fernández-Real JM, Bulló M, Moreno-Navarrete JM, et al. A Mediterranean Diet Enriched with Olive Oil Is Associated with Higher Serum Total Osteocalcin Levels in Elderly Men at High Cardiovascular Risk. The Journal of Clinical Endocrinology & Metabolism. Published online August 1 2012

 

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Can dark chocolate help control blood pressure? PDF Print E-mail

"Chocolate … could reduce blood pressure," BBC News reports.

The report is based on a well conducted review that has pooled the results of trials investigating the effects of chemicals called flavanols. Flavanols are found in cocoa products, such as cocoa powder, dark chocolate and, to a lesser extent, milk chocolate. They are thought to widen blood vessels, causing a drop in blood pressure.

While the researchers did find a statistically significant reduction in blood pressure, the average reduction was relatively modest – a drop of 2-3mmHg.

It is not possible to say whether this small difference could have a positive effect on health or reduce risk of cardiovascular events, such as heart attack. As the researchers point out, this small drop may be useful if other methods, such as regular exercise, are also used to reduce blood pressure.

It is also worth noting that the trials only lasted a few weeks, so it is not possible to tell what the longer term effects would be – both in terms of pros and cons. The trials also varied widely in the dose of flavanol that was given, so it is difficult to determine what the ideal dose would be.

Chocolate in moderation can be part of a healthy balanced diet, but it is high in fat and calories. If eaten in excess any possible beneficial effects are likely to be outweighed by the risk of obesity, which itself increases the chance of high blood pressure and heart disease.

 

Where did the story come from?

This review was authored by members of The Cochrane Collaboration, an international, independent, not-for-profit organisation that produces systematic reviews. The current review was supported by The University of Adelaide, Australia, and the Australian Government Primary Health Care Research Evaluation Development (PHCRED) programme. The individual trials included in the review received funding from various sources, which included in some cases cocoa industries and companies. The authors of the review took into account the potential bias of funding sources into their analyses.

BBC News gives accurate and balanced coverage of this research and they did stress that “there are healthier ways of lowering blood pressure”.

 

What kind of research was this?

This was a systematic review and meta-analysis that aimed to identify all trials investigating the effects of chocolate or cocoa products on blood pressure, and then pool their results. The authors say that the flavanol chemicals that are found in cocoa stimulate nitric oxide, which causes dilation (widening) of blood vessels, and so may be linked to lowering blood pressure. In general, the darker the chocolate is the more flavanols it contains, so the researchers were examining products known to be high in flavanol, such as dark chocolate.

The possible cardiovascular effects of chocolate have been frequently studied in the past. A systematic review published last year looked at the results of observational studies examining the effect of chocolate consumption on the risk of cardiovascular disease. This review found some evidence of an association, but its results were limited as the studies included were observational studies and not randomised controlled trials.

A systematic review including all relevant randomised controlled trials is the best way of investigating the effect of a particular intervention (in this case, cocoa or chocolate) upon an outcome (in this case, blood pressure). Systematic reviews may have limitations if the trials they include have different designs and methods, such as differences in study population, intervention dose and comparator, trial duration, and measurement of outcomes. When the results of the different trials vary significantly from each other as a result, this is known as heterogeneity. 

 

What did the research involve?

The authors searched relevant electronic medical databases to identify all randomised controlled trials that were of at least two weeks’ duration and had compared the effects of chocolate or cocoa products on blood pressure with a control product. The control could be either a flavanol-free or low-flavanol product, but if the control did contain flavanols they had to be less than 10% of the dose in the chocolate or cocoa being tested. The trials could include adults either with or without high blood pressure (hypertension).

The main outcome of interest was the difference in systolic (the upper figure of the two-figure blood pressure measurement, for example 120 in 120/80) and diastolic blood pressure (the lower of the two figures) at final follow-up between cocoa and control group. Other outcomes of interest included compliance with treatment, and adverse effects or intolerance of treatment.

Researchers assessed the quality of the trials and took into account any bias that might influence study results, and any difference in study results. They pooled results of all trials looking at the effects of cocoa or chocolate upon blood pressure, and also separate analyses for trials that used a flavanol-free control group, and those that used low-flavanol controls.

 

What were the basic results?

The researchers identified 20 relevant studies, which included 856 mainly healthy adults. Trial duration varied between two and 18 weeks, the average duration being 4.4 weeks. The daily flavanol dose in the intervention group ranged between 30 and 1,080mg, the average dose being 545.5mg of flavanols contained in between 3.6 and 105g of cocoa products. In 12 trials the control group was given a flavanol-free product, and in the remaining eight trials the control was cocoa powder that contained a low dose of flavanols (between 6.4 and 41mg).

Pooled results of all trials revealed a small, but statistically significant, greater reduction in blood pressure with flavanol-rich cocoa products compared with control:

  • a 2.77mmHg greater reduction in systolic BP in the intervention group compared with control (95% confidence interval of the difference between the two groups 4.72 to 0.82mmHg)
  • a 2.20mmHg greater reduction in diastolic BP in the intervention group compared with control (95% confidence interval of the difference between the two groups 3.46 to 0.93mmHg)

Analyses restricted to those trials where the control was a flavanol-free product still observed a significant difference in blood pressure between the intervention and control groups. However, those trials that had compared a high-dose flavanol product with a low-flavanol control found no significant difference between the two groups.

The researchers found that in the nine short-term trials (only two weeks’ duration) there was a significant blood pressure difference between groups. However, in 11 trials of greater than two weeks’ duration there was no significant difference in blood pressure between groups. The researchers noted that the significant difference in the two-week trials may have been due to the fact that seven out of these nine trials had a flavanol-free control group.

Adverse effects, including digestive complaints and distaste in the mouth, were reported by 5% of participants in the cocoa intervention groups compared with 1% of participants in the control groups.

 

How did the researchers interpret the results?

The researchers conclude that “flavanol-rich chocolate and cocoa products may have a small but statistically significant effect in lowering blood pressure by 2-3mmHg in the short term”. They do, however, acknowledge that differences between the design and results of the studies limit the ability to draw any firm conclusions.

 

Conclusion

This was a well conducted systematic review that combined the results of all trials that have investigated whether cocoa or flavanol-rich chocolate have an effect on blood pressure in predominantly healthy adults. The researchers did find a small but statistically significant 2-3mmHg difference in blood pressure between the intervention and control groups. However, there are important points to be aware of, including:

Trials were of short duration

All of the trials were of short duration, the average being four weeks. The researchers say that they were unable to identify any randomised controlled trials that tested the effect of longer-term daily ingestion of cocoa products. Also of note is that the analyses that were restricted to the trials that were two weeks or longer found no significant difference in blood pressure between the groups. Therefore, we do not have any evidence on the longer-term effects on blood pressure or whether there may be unidentified side effects linked to the long-term consumption of flavanol-rich chocolates or cocoa.

Clinical relevance of the outcomes

None of the trials examined clinical outcomes related to high blood pressure, such as heart disease or strokes. It is, therefore, not possible to say whether the small 2-3mmHg difference in blood pressure measure after the trial would have actually made any difference to the health of the person or influence their cardiovascular risk.

Uncertain ideal dose of flavanol

The trials varied widely in the dose of flavanol or cocoa that was used. In trials comparing high-flavanol with low-flavanol products no blood pressure difference was found, only in those trials comparing high-flavanol with flavanol-free controls. From this it is not possible to say what the ideal dose of flavanol would be and, as the researchers say, trials comparing low-flavanol with flavanol-free products would be valuable to see whether a lower dose has an effect on blood pressure.

Limited populations studied

The authors also say that, although they did analyses looking at participants of different age, body mass index or starting blood pressure, they do not have firm evidence of what the pressure effects would be in different population groups, and this would require assessment in further trials.

Risk-benefit balance

Chocolate in moderation can be part of a healthy balanced diet, but it is high in fat and calories. If eaten in excess any possible beneficial effect upon blood pressure is likely to be outweighed by the risk of becoming overweight or obese, which increases risk of cardiovascular disease and many other chronic diseases.

There are far more effective and healthier ways to reduce blood pressure, such as:

  • reducing your consumption of salt (no more than 6g a day)
  • taking regular exercise
  • losing weight if you are overweight or obese

Read more about preventing high blood pressure.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.

Links To The Headlines

Dark chocolate 'may lower blood pressure'. BBC News, August 15 2012

Chocolate 'lowers blood pressure'. The Independent, August 15 2012

Eating chocolate could be a tasty new way to lower blood pressure. Daily Mail, August 15 2012

Links To Science

Ried K, Sullivan TR, Fakler P, Frank OR, Stocks NP. Effect of cocoa on blood pressure. Cochrane Database of Systematic Reviews. Published online August 15 2012

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'Yo-Yo' diets 'not a No-No' PDF Print E-mail

The Daily Mail informs us that “yo-yo dieting is NOT bad for you and won’t stop you losing weight in the long run”.

The news is based on a study of overweight or obese postmenopausal women who had a history of repetitive “weight cycling” (also known as yo-yo dieting). It looked at whether they were at a disadvantage compared with those without a history of weight cycling when it came to losing weight. The researchers randomly assigned women to spend a year on a programme of either:

  • reduced diet only
  • exercise only
  • a combination of both exercise and diet
  • a control intervention – that is no change to either diet or exercise

They found that women considered ‘weight cyclers’ had body measures that did not differ between groups at the end of the trials, and that they were not at a disadvantage for weight loss.

There are some limitations to this study, however, including the fact that there is no standard definition of weight cycling and that some information was self-reported by the women, which may affect the reliability of the results.

The study does not provide evidence that yo-yo dieting is effective in helping you lose weight. However, the researchers doBut it does highlight an important point – that ‘yo-yo’ dieters should not be put off further attempts to lose weight.

 

Where did the story come from?

The study was carried out by researchers from the US Fred Hutchinson Cancer Research Center, the University of Washington and other US institutions. It was funded by the Canadian National Cancer Institute, the National Institute of Health and the Canadian Institutes of Health Research. The study was published in the peer-reviewed journal Metabolism.

The story was covered by the Daily Mail, and the headline is misleading. The researchers did not find that yo-yo diets wre not bad for you. If anything the study found that women with a history of yo-yo dieting tended to be heavier than women who didn’t yo-yo diet.

What the researchers did find was that yo-yo diets were not as harmful as previously thought.

In addition, the headline implies that this study is relevant to the general population when in fact it only applies to postmenopausal overweight and obese women.

 

What kind of research was this?

This was a randomised controlled trial investigating the effects of dietary or exercise weight loss interventions on body composition and other biological measures. In particular, it aimed to see whether adherence to weight loss interventions and their effects would differ in women with and without a history of weight cycling. 

A randomised controlled trial is a type of study that compares the effects of an intervention with another intervention or a control (such as a placebo). Participants are randomly allocated to which of these they receive. This is the best type of study design to determine the effects of a treatment.

The researchers say that no other studies have looked at this question before.

 

What did the research involve?

Between 2005 and 2009, the researchers recruited 439 postmenopausal women aged between 50 and 75 years to their study. To be eligible, the women had to be overweight or obese (considered as a body mass index [BMI] of more than 25kg/m2, or more than 23kg/m2 for Asian-American women). Women were excluded if they:

  • did more than 100 minutes of moderate activity a week
  • took medications for diabetes or had a fasting blood glucose of more than 7mmol/L
  • had a history of breast cancer or any other serious medical condition
  • were taking hormone replacement therapy or weight loss medications
  • were a current smoker or drank more than two alcoholic beverages a day

Eligible women were then randomly assigned to one of four groups for a period of one year:

  • reduced calorie diet intake only (n=118)
    moderate to vigorous intensity exercise only (n=117)
  • reduced calorie diet intake plus moderate to vigorous intensity exercise (n=117)
  • no intervention (n=87)

To assess weight cycling study participants were asked at the beginning of the study: “Since you were 18 years old, how many different times did you lose each of the following amounts of weight on purpose (excluding pregnancy or illness)?” Various weight ranges were provided ranging from 5lb to more than 100lb and possible responses were from one to more than seven for each amount of weight loss. Women who reported losing more than 20lb on three or more occasions were considered by the researchers to be “severe weight cyclers”. Women who reported losing between 10lb and 20lb on more than three occasions were considered to be “moderate weight cyclers” and all other women were considered to be “non-cyclers”.

The researchers measured changes in body composition known to have an effect on health, such as:

  • weight
  • blood pressure
  • blood sugar
  • insulin levels
  • various other blood chemicals, such as C-reactive protein (a protein associated with inflammation)

They then analysed their results using statistical methods adjusting for BMI.

 

What were the basic results?

Overall, 24% of women met the criteria for moderate weight cycling and 18% met criteria for “evere weight cycling” At the start of the study, these women weighed more and had less favourable metabolic characteristics than women considered to be “non-cyclers”

The key finding of this study was that after one year, participants considered to be weight cyclers” (moderate and severe), did not significantly differ in most of the body composition measures compared with those considered to be “on cyclers” In addition, adherence to the different study groups did not significantly differ across groups.

 

How did the researchers interpret the results?

The researchers conclude that a history of weight cycling does not impede successful participation in diet or exercise interventions or alter their benefits on body composition and physiological outcomes.

In discussing the research findings, lead researcher Dr Anne McTiernan says: “A history of unsuccessful weight loss should not dissuade an individual from future attempts to shed pounds or diminish the role of a healthy diet and regular physical activity in successful weight management”.

 

Conclusion

Overall, this study provides evidence to support the use of well structured austaht lossinterventions for women known to have a history of repetitive weight cycling.

There are some limitations to this study, some of which the researchers note:

  • there is no standard definition of weight cycling, which may make comparisons to other studies difficult
  • weight cycling was determined by self-report, which can make results less reliable
  • there were difficulties in differentiating between unintentional weight loss and intentional weight loss of participants, which may affect the results
  • it is possible that women did not accurately report their exercise and dietary behaviours correctly, which also could affect the accuracy of the results (although the researchers did ask participants to record their activity or dietary intake and wear a pedometer for one week)

In conclusion, these findings may help to encourage overweight and obese postmenopausal women to reach a healthy weight through following structured weight loss interventions. The study does not provide evidence that yo-yo dieting is effective in helping you lose weight.

Links To The Headlines

'Yo-yo dieting is NOT bad for you and won't stop you losing weight in the long run'. Daily Mail, August 16, 2012

Links To Science

Mason C, Foster-Schubert KE, Imayama I, et al. History of weight cycling does not impede future weight loss or metabolic improvements in postmenopausal women. Metabolism. Published online August 14 2012

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NHS faces spiralling diabetes prescription costs - The Press, York PDF Print E-mail

The Guardian

NHS faces spiralling diabetes prescription costs
The Press, York
THE NHS in York and North Yorkshire faces a spiralling number of future diabetes prescriptions experts have warned. The figures from the Health and Social Care Information Centre (HSCIC) show the number of prescriptions attributed to diabetes during ...
Obesity and diet fuel £760million diabetes bill for NHSMetro
We face the real possibility of diabetes bankrupting the NHS within a ...Daily Mail
Diabetes prescriptions top 40mThe Press Association
BBC News -The Guardian -Netdoctor
all 121 news articles »
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