Tag: diet

Study Reveals Diet is the Main Risk Factor for Colon Cancer in Younger Adults

Photo by Alex Haney

A new Cleveland Clinic study has identified diet-derived molecules called metabolites as main drivers of young-onset colorectal cancer risk, especially those associated with red and processed meat. The NPJ Precision Oncology report, which analysed metabolite and microbiome datasets, highlighted that one of the best ways a younger ( < 60 years) adult can prevent colorectal cancer is to discuss their diet with their doctor.

Increased monitoring and screening for colorectal cancer is an extremely helpful tool. Despite the success of these methods, these data indicate physicians can take a different approach with their younger patients, says senior author and gastrointestinal oncologist Suneel Kamath,MD.

“At the end of the day, it’s impractical to apply our care models for those over 60 to younger adults simply because we cannot give everyone in the system yearly colonoscopies,” he explains. “What is much more feasible is to give everyone in the system a simple test to measure a biomarker that determines their colorectal cancer risk. Then we can give the most at-risk individuals appropriate screening.”

Former clinical fellow Thejus Jayakrishnan, MD, and Naseer Sangwan, PhD, director of the Microbial Sequencing & Analytics Resource Core co-led the work. Researchers in Cleveland Clinic’s Center for Young-Onset Colorectal Cancer provided large-scale analyses of patient data from individuals who received care for either young- or average-onset colorectal cancer at Cleveland Clinic.

One previous study from this team identified differences in the metabolites (diet-derived molecules) of young – versus average-onset colorectal cancer, while another identified differences in gut microbiome between younger and older adults with colorectal cancer. These studies provided many potential directions for studying young-onset CRC. However, when more factors are involved in cancer risk, it becomes more complicated to understand what’s going on and plan future research, Dr Sangwan says. Interactions between these factors, like when our gut bacteria consume our metabolites and produce their own, make it even more complex.

Dr Sangwan and his team then developed an AI algorithm to combine and analyse the existing studies’ datasets and clarify what factors are most relevant for future study. Surprisingly, Dr Sangwan’s analysis revealed that differences in diet (identified through analysing metabolites) accounted for a significant proportion of the differences observed between the young-onset and older-onset patients.

“Researchers – ourselves included – have begun to focus on the gut microbiome as a primary contributor to colon cancer risk. But our data clearly shows that the main driver is diet,” Dr Sangwan says. “We already know the main metabolites associated with young-onset risk, so we can now move our research forward in the correct direction.”

The team was excited to see diet play such a large role in cancer risk, because it is much easier to identify at-risk patients by counting the metabolites in their blood than it is to sequence the bacterial DNA in their stool for different microbes.

“It can actually be very complicated and difficult to change your microbiome,” explains Dr Kamath. “While it’s not always easy, it is much simpler to change your diet to prevent colon cancer.”

Addressing factors in our diet to prevent colon cancer

Younger colon cancer patients had higher levels of metabolites associated with the production and metabolism of an amino acid called arginine, and with the urea cycle compared to their older peers. These differences may be tied to long-term consumption of red meat and processed meat. The team is now analyzing national datasets to validate their Cleveland Clinic-specific findings in patients across the country.

After they show that arginine and urea cycle metabolites (and, by proxy, red and processed meat overconsumption) are elevated across younger adults with colon cancer nationwide, they plan to test whether certain diets or commercially available drugs that regulate arginine production and the urea cycle can help prevent or even treat young-onset colorectal cancer.

Dr Kamath says that even though more research is needed to understand exactly how dietary factors cause colon cancer, his current findings have already changed the way he delivers patient care.

“Even though I knew before this study that diet is an important factor in colon cancer risk, I didn’t always discuss it with my patients during their first visit. There is so much going on, it can already be so overwhelming,” says Dr Kamath. “Now, I always make sure to bring it up to my patients, and to any healthy friends or family members they may come in with, to try and equip them with the tools they need to make informed choices about their lifestyle.”

Source: Cleveland Clinic

Steaks are OK? Global Study Challenges Current Advice on High-fat Diets

Photo by Jose Ignacio Pompe on Unsplash

In a study conducted across 80 countries, researchers found that unprocessed red meat and whole grains can be included or left out of a healthy diet. Published in the European Heart Journal, the findings showed that diets emphasising fruit, vegetables, dairy (mainly whole-fat), nuts, legumes and fish were linked with a lower risk of cardiovascular disease (CVD) and premature death in all world regions. The addition of unprocessed red meat or whole grains had little impact on outcomes.

“Low-fat foods have taken centre stage with the public, food industry and policymakers, with nutrition labels focused on reducing fat and saturated fat,” said study author Dr Andrew Mente of the Population Health Research Institute, McMaster University, Hamilton, Canada. “Our findings suggest that the priority should be increasing protective foods such as nuts (often avoided as too energy dense), fish and dairy, rather than restricting dairy (especially whole-fat) to very low amounts. Our results show that up to two servings a day of dairy, mainly whole-fat, can be included in a healthy diet. This is in keeping with modern nutrition science showing that dairy, particularly whole-fat, may protect against high blood pressure and metabolic syndrome.”

The study examined the relationships between a new diet score and health outcomes in a global population. A healthy diet score was created based on six foods that have each been linked with longevity. The PURE diet included 2-3 servings of fruit per day, 2-3 servings of vegetables per day, 3-4 servings of legumes per week, 7 servings of nuts per week, 2-3 servings of fish per week, and 14 servings of dairy products (mainly whole fat but not including butter or whipped cream) per week. A score of 1 (healthy) was assigned for intake above the median in the group and a score of 0 (unhealthy) for intake at or below the median, for a total of 0 to 6. Dr Mente explained: “Participants in the top 50% of the population – an achievable level – on each of the six food components attained the maximum diet score of six.”

Associations of the score with mortality, myocardial infarction, stroke and total CVD (including fatal CVD and non-fatal myocardial infarction, stroke and heart failure) were tested in the PURE study which included 147 642 people from the general population in 21 countries. The analyses were adjusted for factors that could influence the relationships such as age, sex, waist-to-hip ratio, education level, income, urban or rural location, physical activity, smoking status, diabetes, use of statins or high blood pressure medications, and total energy intake.

The average diet score was 2.95. During a median follow-up of 9.3 years, there were 15 707 deaths and 40 764 cardiovascular events. Compared with the least healthy diet (score of 1 or less), the healthiest diet (score of 5 or more) was linked with a 30% lower risk of death, 18% lower likelihood of CVD, 14% lower risk of myocardial infarction and 19% lower risk of stroke. Associations between the healthy diet score and outcomes were confirmed in five independent studies including a total of 96 955 patients with CVD in 70 countries.

Dr Mente said: “This was by far the most diverse study of nutrition and health outcomes in the world and the only one with sufficient representation from high-, middle- and low-income countries. The connection between the PURE diet and health outcomes was found in generally healthy people, patients with CVD, patients with diabetes, and across economies.”

“The associations were strongest in areas with the poorest quality diet, including South Asia, China and Africa, where calorie intake was low and dominated by refined carbohydrates. This suggests that a large proportion of deaths and CVD in adults around the world may be due to undernutrition, that is, low intakes of energy and protective foods, rather than overnutrition. This challenges current beliefs,” said Professor Salim Yusuf, senior author and principal investigator of PURE.

In an accompanying editorial, Dr Dariush Mozaffarian of the Friedman School of Nutrition Science and Policy, Tufts University, USA, stated: “The new results in PURE, in combination with prior reports, call for a re-evaluation of unrelenting guidelines to avoid whole-fat dairy products. Investigations such as the one by Mente and colleagues remind us of the continuing and devastating rise in diet-related chronic diseases globally, and of the power of protective foods to help address these burdens. It is time for national nutrition guidelines, private sector innovations, government tax policy and agricultural incentives, food procurement policies, labelling and other regulatory priorities, and food-based healthcare interventions to catch up to the science. Millions of lives depend on it.”

Source: European Society of Cardiology

Female Athletes’ Metabolism Drops if They Cut Energy Intake

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Most athletes know that diet and training go hand in hand for the best results, and many of them closely monitor their energy intake and training. However, a new study from Aarhus University shows that the bodies of female athletes are negatively affected when they consume too little energy through their diet in comparison with their training volume, explains PhD student Mikkel Oxfeldt. He and Associate Professor Mette Hansen are behind the study, which is published in the Journal of Physiology.

“We know that both elite female athletes and active women at times, either consciously or unconsciously, don’t have an energy intake that matches their energy expenditure when training. The study shows that insufficient energy intake can negatively affect muscles’ ability to respond to training. After just ten days of low energy intake, we began seeing changes to the hormonal system such as a decrease in the metabolic hormone followed by a decrease in metabolism.”

The study shows that it is important that women are careful not to reduce their energy intake too much. In fact, they should actually be increasing their energy intake if they increase their training volume, says Mikkel Oxfeldt:

“When you don’t get enough energy from your diet, your body will begun to pare down processes that require a lot of energy, just like a mobile phone that goes into battery-saving mode. We know from previous studies that it can cause some women’s periods to stop. However, our results show that other processes in the body, such as building new muscle proteins, are also affected.”

We must confront the unilateral focus on weight

Thirty fit women aged 18–30 participated in the study which is part of the Novo Nordic-funded Team Denmark network called ‘competition preparation and training optimisation’. All the women started the study right after the start of their menstrual period and followed a very controlled training and diet regimen for three weeks.

“Under the supervision of the researchers, the participants carried out individual training programmes aimed at increasing muscle mass, strength and overall fitness. The women’s meals were also provided by us. By controlling their training regimen and their diets, we were able to see how much energy they expended and what they ate during the study,” says Mikkel Oxfeldt and continues:

“This is the first time that such a well-controlled study has been carried out in this area, where both the diet and training of a group of fit women has been regulated to this extent. During the study, all participants drank doubly labelled water, which is enriched with a trace material. When we combine this tracer technique with the retrieval and subsequent analysis of muscle tissue samples, we can gain detailed insight into the muscles’ response to the experimental protocol,” explains Mikkel Oxfeldt.

Mikkel and the research group believe it’s necessary to confront the idea that weight loss leads to medals when in fact weight loss can negatively impact a number of the body’s systems, including muscles.

“In recent years, we’ve heard about public weigh-ins within some elite sports. They are part of promoting a culture in which some women are constantly trying to lose weight. However, our results show that this focus on weight loss can have short and potentially long-term negative consequences for women, both in relation to their health and training results. The study will hopefully provide athletes and coaches with a more nuanced picture of possible side effects.”

In collaboration with colleagues from the University of Copenhagen and University of Southern Denmark, the researchers behind the study are now investigating how physical performance, the immune system and metabolism are affected by an insufficient energy intake. They hope to one day be able to establish whether there is a difference between how women’s and men’s bodies react to inadequate energy intake.

Source: Aarhus University

Processed Foods Increase Miscarriage Risk; Fruits Reduce it

A preconception and early-pregnancy diet that contains lots of fruit, vegetables, seafood, dairy, eggs and grain may be associated with reducing risk of miscarriage, suggests a new review of research in the journal Fertility and Sterility.

University of Birmingham researchers analysed 20 studies on eating habits in the months before and shortly after conceiving a baby to see whether these studies showed evidence of association with a lower or higher chance of miscarriage. The team conclude that there is evidence to suggest a diet rich in fruit, vegetables, seafood, dairy products, eggs and grain reduces miscarriage risk.

Not surprisingly, these are foods which typically make up ‘healthy’ well-balanced diets, with previous evidence showing that eating a well-rounded diet which is rich in vitamins and minerals during pregnancy is important.

The research review found that, when compared to low consumption, high intake of fruit may be associated with a 61% reduction in miscarriage risk. High vegetable intake may be associated with a 41% reduction in miscarriage risk. For dairy products it is a 37% reduction, 33% for grains, 19% for seafood and eggs.

Led by Dr Yealin Chung, researchers also looked at whether pre-defined dietary types, such as the Mediterranean Diet or Fertility Diet could also be linked to miscarriage risk. They could not find evidence that following any of these diets lowered or raised risk.

However, a whole diet containing healthy foods overall, or foods rich in antioxidant sources, and low in pro-inflammatory foods or unhealthy food groups may be associated with a reduction in miscarriage risk for women.

A diet high in processed food was shown to be associated with doubling of miscarriage risk.

The studies included in the analysis focused on the peri-conception period, which is before and during the first 3 months of pregnancy. Data collected from a total of 63 838 healthy women of reproductive age was included, with information on their diets typically collected through food frequency questionnaires for each study.

Dr Chung explains:

“Miscarriage is common, with estimates suggesting 1 in 6 pregnancies end in miscarriage, and there are many known causes, from problems with the baby’s chromosomes to infections in the womb.

“Yet nearly 50% of early pregnancy losses remain unexplained and in the absence of a cause, parents often turn to their healthcare providers for guidance on the best ways to be as healthy as possible and reduce the risk of future miscarriages.

“There’s a growing body of evidence to show that lifestyle changes – including changes to diet, stopping smoking and not drinking alcohol – before conceiving and in your pregnancy’s early stages – may have an impact.”

Source: University of Birmingham

You Can’t Outrun a Poor Diet, Large Study Shows

Tired woman after exercise
Photo by Ketut Subiyanto on Pexels

New research reported in the British Journal of Sports Medicine has found that the detrimental effects of a poor diet on mortality risk are not counteracted by exercise, showing that you cannot ‘outrun’ a poor diet.

Study participants with both high levels of physical activity and a high-quality diet were found to have the lowest mortality risk.

The University of Sydney-led researchers analysed the independent and joint effects of diet and physical activity with all-cause, cardiovascular disease and cancer mortality using a large population-based sample of 360 600 adults from the UK Biobank.

High quality diets were defined as including at least five portions of fruit and vegetables every day, two portions of fish per week and lower consumption of red meat, particularly processed meat.

The study revealed that for those who had high levels of physical activity and a high-quality diet, their mortality risk was reduced by 17% from all causes, 19% from cardiovascular disease and 27% from selected cancers, as compared with those with the worst diet who were physically inactive.

Lead author Associate Professor Melody Ding at the University of Sydney said: “Both regular physical activity and a healthy diet play an important role in promoting health and longevity.

“Some people may think they could offset the impacts of a poor diet with high levels of exercise or offset the impacts of low physical activity with a high-quality diet, but the data shows that unfortunately this is not the case,” said Associate Professor Melody Ding, the study’s lead author.

small collection of studies have previously found that high-intensity exercise may counteract detrimental physiological responses to over-eating.

However, the long-term effects on how diet and physical activity interact with each other remained less explored. The study findings confirm the importance of both physical activity and quality diet in all-cause and cause-specific mortality.

“This study reinforces the importance of both physical activity and diet quality for achieving the greatest reduction in mortality risk,” said Assoc Prof Ding.

“Public health messages and clinical advice should focus on promoting both physical activity and dietary guidelines to promote healthy longevity.”

Source: The University of Sydney