Category: Diet and Nutrition

Fruit Juices in South Africa Are Getting a Free Ride: Why They Should Have the Same Health Warning Labels as Fizzy Drinks

Siphiwe Dlamini, University of the Witwatersrand

Photo by Eiliv Aceron on Unsplash

South Africa is facing a sharp rise in obesity-related diseases like type 2 diabetes. Between 2010 and 2019, the prevalence of diabetes nearly tripled from 4.5% to 12.7%. This increase is linked to lifestyle risk factors including drinking sugary beverages, eating unhealthy foods, and not getting enough physical activity.

To help tackle the problem, the government has introduced several public health measures targeting key risk factors, including unhealthy eating.

One of the most prominent measures was the introduction of a tax on sugar-sweetened beverages in 2018. The tax targets added sugars, encouraging manufacturers to reformulate products like soft drinks and energy drinks to reduce their sugar content. But beverages containing naturally occurring sugars, such as 100% fruit juices, are exempt.

Often, 100% fruit juices are seen as healthier alternatives to sugar-sweetened or artificially sweetened drinks. But growing research shows this may not be true. A 2023 meta-analysis of 72 published studies involving over 3 million people found that drinking fruit juice does not lower the risk of type 2 diabetes or high blood pressure. It was instead linked to a higher risk of dying from cardiovascular diseases.

The recommendation from that meta-analysis and other studies is that fruit juices should not be considered a healthier alternative to sugar-sweetened beverages. This could be because, although fruit juices contain more vitamins and minerals than soft drinks, they are also high in natural sugars and lack the fibre found in whole fruits, which helps control blood sugar and keeps you feeling full.

In a further move to curb sugar intake in beverages the government has proposed new food labelling regulations. These would require front-of-package warning labels for products high in added sugar, saturated fat, sodium, or artificial sweeteners. The regulations are still under review. But they align with international best practices adopted by countries like Chile, Mexico and Brazil.

If implemented effectively, they could help South African consumers make more informed dietary choices.

But, once again, fruit juices are getting a free ride. This is even though they have the highest energy (calories) and sugar content (8.4%) across a range of soft and energy drinks, according to our recent study.

As researchers in public health nutrition, we are concerned that the regulations had some important gaps. The proposed regulations introduce a simple package warning label system for prepacked foods that contain added sugar, saturated fat, or sodium and exceed specific nutrient thresholds. It also requires warning labels for products containing artificial sweeteners, reflecting growing concerns about their long-term health effects.

But the regulations exclude certain sugar-containing beverages from front-of-pack warning label requirements, particularly those with naturally occurring sugars. Many juices, such as 100% fruit juices, are exempt despite their high sugar content and significant contribution to overall sugar and energy intake. This raises concerns about the consistency of the policy and whether it adequately addresses the health risks associated with excessive sugar consumption across all types of beverages.

To test the scale of the problem, we analysed over 600 non-alcoholic beverages sold in major South African supermarkets. The study found that 21.4% of beverages would require a warning for high sugar, 49.8% for artificial sweeteners, and 58.7% for at least one of these criteria.

Juices were least likely to qualify for warning labels. Only 30% of juices met the criteria , versus 94.1% of soft drinks and 96.9% of energy drinks. Excluding 100% fruit juices from South Africa’s proposed warning label regulations could have serious public health consequences.

We recommend that the health department revise the criteria for warning labels to include beverages that are high in naturally occurring sugars.

Fruit juices

Fruit juices are often seen as a healthier choice because of their natural origin. In South Africa, regular consumption of 100% fruit juice is common, with many consumers perceiving it as beneficial despite its high sugar content.

This is a problem for a number of reasons.

Because of their high sugar content, fruit juices can cause sharp spikes in blood glucose. For more than 2.3 million South Africans living with diabetes regular consumption may interfere with blood glucose control. But this is not only a concern for people with diabetes. Research shows that even among non-diabetics, frequent intake of fruit juice increases weight gain, and the risk of developing type 2 diabetes over time.

Labelling policies that ignore naturally occurring sugars risks misleading consumers. In particular, it misleads those trying to make healthier choices into over-consuming these products. International examples, such as Chile’s approach to food labelling, show that including total sugar content in warning criteria can reduce purchases of high-sugar items and improve public awareness.

Exempting juices also creates an uneven playing field. While soft drink and energy drink manufacturers are pushed to reformulate products to avoid taxes and warning labels, juice producers face no such pressure, despite offering products with comparable health risks.

We also demonstrated that nearly half of the beverages analysed contained artificial sweeteners, which are increasingly used to lower sugar content and bypass the sugar tax. Emerging research suggests these additives may negatively affect gut health and contribute to nutrition-related diseases. Taken together, these factors highlight the need for comprehensive regulation that reflects the full spectrum of health risks posed by sugary beverages.

Next steps

South Africa’s efforts to regulate sugary beverages are commendable and reflect a growing commitment to tackling lifestyle-related diseases. But excluding fruit juices from key policies risks undermining these efforts.

By aligning regulations with scientific evidence and international best practices, the country can take a more comprehensive approach to sugar reduction. This approach will protect all consumers, especially the most vulnerable.

To ensure that South Africa’s food labelling regulations achieve their intended public health outcomes, we recommend the following steps.

  • Include naturally occurring sugars: Revise the criteria for warning labels to account for total sugar content, not just added sugars. This would ensure that high-sugar juices are appropriately labelled, and consumers are fully informed.
  • Extend the sugar tax: Consider applying the sugar tax to fruit juices with high sugar content. This would encourage manufacturers to explore lower-sugar formulations.
  • Public education campaigns: Launch targeted education initiatives to raise awareness about the health risks associated with all types of sugar, including those found in fruit juices.
  • Ongoing monitoring: Establish systems to monitor the impact of both labelling and taxation policies on consumer behaviour and health outcomes, allowing for evidence-based adjustments over time.

Siphiwe Dlamini, Lecturer, Department of Physiology, University of the Witwatersrand

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Ultra-processed Food Intake Linked to Prediabetes in Young Adults

Researchers tracked 85 young adults over a four-year period, finding that increases in ultra-processed food consumption were linked with elevated blood sugar and early signs of diabetes risk.

Photo by Jonathan Borba

More than half of calories consumed in the United States come from ultra-processed foods (UPFs), items like fast food and packaged snacks that are often high in sodium, sugar and unhealthy fats. In adults, research has clearly linked these foods to type 2 diabetes and other conditions, but few studies have explored their effects among youth.

Now, researchers from the Keck School of Medicine of USC have completed one of the first studies to examine the link between UPF consumption and how the body processes glucose, which is known to predict diabetes risk. By tracking changes over time, they gained insights into how dietary choices may influence key biological processes.

The researchers studied a group of 85 young adults over a four-year period. They found that an increase in UPF intake was associated with a higher risk for prediabetes, or early-stage high blood sugar that can lead to diabetes. Eating more UPFs was also linked to insulin resistance, where the body becomes less effective at using insulin to control blood sugar. The study, funded in part by the National Institutes of Health, was just published in the journal Nutrition and Metabolism.

“Our findings show that even modest increases in ultra-processed food intake can disrupt glucose regulation in young adults at risk for obesity. These results point to diet as a modifiable driver of early metabolic disease, and an urgent target for prevention strategies among young people,” said senior author Vaia Lida Chatzi, MD, PhD, a professor of population and public health sciences and paediatrics and director of the ShARP Center at the Keck School of Medicine.

Early adulthood is a formative stage where people have reached physical maturity and are building habits that can persist for years. Trading packaged or restaurant meals for whole and raw foods like fruits, vegetables, and whole grains can reduce the likelihood of developing type 2 diabetes later in life.

“Young adulthood is a critical window for shaping long-term health,” Chatzi said. “By focusing on young adults, we have an opportunity to intervene early, before prediabetes and other risk factors become lifelong conditions.”

Signs of prediabetes

 The research included 85 young adults from the Metabolic and Asthma Incidence Research (Meta-AIR) study, part of the broader Southern California Children’s Health Study. Participants, aged 17–22, provided data at a baseline visit between 2014 and 2018 and a follow-up visit approximately four years later.

At each visit, participants reported everything they had eaten on one recent weekday and one recent weekend day. Researchers classified foods into two categories: UPFs (such as candy, soda, cereal, packaged spreads, flavored yogurts, and many restaurant foods) and foods that were not ultra-processed. They then calculated what percentage of each participant’s daily caloric intake came from UPFs.

The researchers also collected blood samples from participants before and after they consumed a sugary drink to test how effectively their body responded to blood sugar with insulin. They then conducted a statistical analysis to compare dietary changes with signs of prediabetes, adjusting for differences in age, sex, ethnicity and physical activity levels.

From baseline to follow-up, a 10% increase in UPF consumption was associated with a 64% higher risk for prediabetes and a 56% higher risk for problems with glucose regulation. Participants who reported eating more UPFs at their initial visit were also more likely to have elevated insulin levels at follow-up—an early sign of insulin resistance, where the body must produce more insulin to keep blood sugar in a healthy range.

Limiting ultra-processed foods

The study shows that the risks of UPFs extend to young adults, a group often overlooked in previous research.

“These findings indicate that ultra-processed food consumption increases the risk for pre-diabetes and type 2 diabetes among young adults – and that limiting consumption of those foods can help prevent disease,” said the study’s first author, Yiping Li, a doctoral student in quantitative biomedical sciences at Dartmouth College who previously worked as a researcher at the Keck School of Medicine.

Future studies with larger groups and more detailed diet tracking can help clarify which foods pose the greatest risk for young adults, the researchers said. They also plan to continue investigating the biological mechanisms behind these links, including how specific nutrients in UPFs may influence insulin and blood sugar regulation.

Source: Keck School of Medicine of USC

Plant-based Nutrient Improves Immune Cells’ Cancer-Fighting Power

Researchers find that zeaxanthin, best known for protecting vision, can also strengthen the cancer-fighting activity of immune cells.

Zeaxanthin is a carotenoid, a type of yellow-orange pigment found in plants. It is found in food such as yellow peppers and maize. Photo by Daniel Dan on Unsplash

In a new study, researchers from the University of Chicago discovered that zeaxanthin, a plant-derived carotenoid best known for protecting vision, may also act as an immune-boosting compound by strengthening the cancer-fighting activity of immune cells. The findings, which were published in Cell Reports Medicine, highlight the potential of zeaxanthin as a widely available supplement to improve the effectiveness of cancer immunotherapies.

“We were surprised to find that zeaxanthin, already known for its role in eye health, has a completely new function in boosting anti-tumour immunity,” said Jing Chen, PhD, Professor of Medicine and senior author of the study. “Our study show that a simple dietary nutrient could complement and strengthen advanced cancer treatments like immunotherapy.”

How does this nutrient work?

The study builds on years of work by Chen’s lab to better understand how nutrients influence the immune system. By screening a large blood nutrient library, the team identified zeaxanthin as a compound that directly enhances the activity of CD8+ T cells, a crucial type of immune cell that kills tumour cells. These cells rely on a molecular structure called the T-cell receptor (TCR) to recognise and destroy abnormal cells.

The researchers found that zeaxanthin stabilizes and strengthens the formation of TCR complex on CD8+ T cells upon interacting with the cancer cells. This, in turn, triggers more robust intracellular signaling that boosts T-cell activation, cytokine production, and tumour-killing capacity.

Zeaxanthin improves immunotherapy effects

In mouse models, dietary supplementation with zeaxanthin slowed tumour growth. Importantly, when combined with immune checkpoint inhibitors – a type of immunotherapy that has transformed cancer treatment in recent years – zeaxanthin significantly enhanced anti-tumour effects compared to immunotherapy alone.

With more research, we may discover natural compounds that make today’s cancer therapies more effective and accessible.

Jing Chen, PhD

To extend the findings, the researchers tested human T cells engineered to recognise specific tumour antigens and found that zeaxanthin treatment improved these cells’ ability to kill melanoma, multiple myeloma, and glioblastoma cells in laboratory experiments.

“Our data show that zeaxanthin improves both natural and engineered T-cell responses, which suggests high translational potential for patients undergoing immunotherapies,” Chen said.

A safe and accessible candidate

Zeaxanthin is sold as an over-the-counter supplement for eye health, and is naturally found in vegetables like orange peppers, spinach, and kale. It’s inexpensive, widely available, well-tolerated and, most importantly, its safety profile is known – which means it can be safely tested as an adjunct to cancer therapies.

The study also reinforces the importance of a balanced diet. In their previous research, Chen’s group discovered that trans-vaccenic acid (TVA), a fatty acid derived from dairy and meat, also boosts T-cell activity – but through a different mechanism. Together, the findings suggest that nutrients from both plant and animal sources may provide complementary benefits to immune health.

Clinical applications of zeaxanthin

Although the results are promising, the researchers stress that the work is still at an early stage. Most of the findings come from laboratory experiments and animal studies. Thus, clinical trials will be needed to determine whether zeaxanthin supplements can improve outcomes for cancer patients.

“Our findings open a new field of nutritional immunology that looks at how specific dietary components interact with the immune system at the molecular level,” Chen said. “With more research, we may discover natural compounds that make today’s cancer therapies more effective and accessible.”

The study, “Zeaxanthin augments CD8+ effector T cell function and immunotherapy efficacy,” was supported by grants from the National Institutes of Health, the Ludwig Center at the University of Chicago, and the Harborview Foundation Gift Fund.

Source: The University of Chicago

AI Nutrition Study Finds “Five Every Day” May Keep the Doctor Away

Photo by Brad West on Unsplash

In a new study using AI and machine learning, EPFL researchers have found that it’s not only what we eat, but how consistently we eat it that plays a crucial role in gut health. Many previous studies have shown that what we eat has an impact on our gut microbiota. Healthy diets rich in fruit, vegetables, fibre and nuts are strongly associated with increased microbial diversity and better stomach health.

But now, for the first time, EPFL research has shown that the regularity with which we eat a healthy diet is just as important for gut health as the amount of what we consume.

The importance of nutritional quality and regularity

In a new paper, just published in the journal Nature Communications, researchers in EPFL’s Digital Epidemiology Laboratory, part of both the Schools of Computer and Communication and Life Sciences, confirmed earlier research that certain types of foods, such as fruit and vegetables, contribute to a more diverse gut microbiota. Working with colleagues at the University of California, San Diego, they also made several striking new discoveries.

First, they found that it’s not just the consumption of fruit, vegetables and grains that create a healthy gut microbiota, but whether you eat them regularly or not. Whilst there’s always been a hunch that it’s important to eat good food regularly, encouraged by campaigns such as ‘five fruits and vegetables a day’, it has always been just that – a hunch.

“This research clearly shows that you cannot binge on vegetables on your healthy day and then eat in an unhealthy way for the rest of the week or month,” said Associate Professor Marcel Salathé, head of the Digital Epidemiology Lab and co-director of the EPFL AI Center. “In fact, our study suggests that irregular consumption of healthy foods undoes many of their beneficial effects on the gut microbiota. This is a real incentive for future studies to not just look at what people are eating but the patterns of what they are eating over time.”

Predicting diet from the microbiome

Second, the team was also able to show that a person’s gut bacteria and what they eat can predict each other with up to 85% accuracy. With just a simple stool sample — an increasingly common component of medical research — advanced machine learning techniques could predict a person’s diet using their microbiota and vice versa.

“For our collaborators in San Diego, who are some of the world’s leading experts in microbiome research, this was exciting,” explained Salathé. “Getting such data from a stool sample is relatively easy, but understanding someone’s diet is notoriously difficult, it’s data that’s been challenging to collect.”

The power of real-time data

The study was made possible by using detailed nutritional information from about 1000 participants who were part of the “Food & You” cohort.

High-resolution dietary data was collected via the AI-powered app MyFoodRepo, developed by the same EPFL lab, which allowed users to log their meals in real time by snapping photos or scanning barcodes. The app’s AI then analysed these entries for nutritional content, later verified by human reviewers.

“Historically, nutrition research has relied on food frequency questionnaires and 24-hour dietary recalls. In theory, you could ask somebody to write down everything they eat but in practice it’s just not done because it’s borderline impossible. Now, the AI is so good that we can do this data collection at a large scale,” said Rohan Singh, a Doctoral Assistant in the Digital Epidemiology Lab and lead author of the paper.

“Our study has been particularly interesting because when you look at lifestyle-oriented gastrointestinal disorders, they often develop gradually. Since nutrition is one of the big contributors to these diseases, analyses like ours may be able to assess what can be improved in a person’s diet. AI can then help nudge people to adjust their food intake accordingly,” he continued.

Looking ahead

Salathé believes the study’s findings suggest that current dietary guidelines may need to be updated to emphasize not just the types and quantities of food, but the regularity of healthy eating behaviors.

And, while this research project has ended, the MyFoodRepo app continues to be used by the Digital Epidemiology Lab team for other research. They are currently involved in a pilot project on nutrition and cognitive performance, studying potential links between the two.

Also, through the use of barcoded food data from the Food & You study, the researchers are investigating the link between food additives, like emulsifiers, found in ultra-processed foods, and the gut microbiota.

“There’s a strong hypothesis that some of these additives really may negatively impact your microbiota, and we have some early indications that this could indeed be the case. We’re still in the analysis stage but we are quite excited about early results,” said Salathé.

More generally, they are gratified that the MyFoodRepo app is now opening the door to important nutrition studies globally.

“From the outset, we knew we needed something extremely consumer friendly and easy to use, while still providing the data that we needed. We built it to serve our own research needs, but also in a way which others would find useful – and it’s now being used in many other nutrition studies globally,” Salathé concluded.

Source: Ecole Polytechnique Federale de Lausanne

Retracted: Widely-reported Trial on Apple Cider Vinegar and Weight Loss

Journalists and others should no longer reference or use the study findings in future reporting

Photo by Kenny Eliason on Unsplash

BMJ Group has retracted research suggesting that small daily quantities of apple cider vinegar might help people who are overweight or obese to lose weight.

The small clinical trial was published in the open access journal BMJ Nutrition, Prevention & Health in March 2024 and its findings press released. The study findings generated widespread international attention at the time, and continue to be frequently referred to in media coverage.

The retraction was prompted by concerns raised about the quality of the work, including the approach to statistical analysis of the data; implausible statistical values; the reliability of the raw data; inadequate reporting of methods; and lack of prospective trial registration, which breaches BMJ Group’s editorial policy.

Initially, concerns were raised in critiques of the study, some of which were published as letters in the journal. But after review by BMJ Group’s content integrity team, the study was referred to statistical experts to evaluate its reliability.  This included attempts to replicate the results and examine the authenticity of the underlying data supplied by the authors.

It wasn’t possible for the statisticians to replicate the results and multiple analytical errors were identified. There were also irregularities in the data set, and their report, which is appended to the retraction notice, concluded that the data collected from each participant would require further independent scrutiny.

The authors said that the identified errors were honest mistakes, but they agree with the decision to retract the study.

Dr Helen Macdonald, Publication Ethics and Content Integrity Editor at BMJ Group, said: “Tempting though it is to alert readers to an ostensibly simple and apparently helpful weight loss aid, at present the results of the study are unreliable, and journalists and others should no longer reference or use the results of this study in any future reporting.”

She added: “This retraction reflects our strategic and proactive approach to investigating concerns raised about the content we publish. We act where necessary in the interests of openness and the importance of correcting the scientific record.

“While we deal with allegations as swiftly as possible, it’s very important that due process is followed. Investigations are often complex. This one involved detailed scrutiny of data and correspondence with researchers, institutions, and other experts, for example. Reaching a sound and fair and final decision can therefore take several months.”

Commenting on the decision to publish the study despite the lack of trial registration, Professor Martin Kohlmeier, editor in chief of BMJ Nutrition Prevention & Health, explained: “In hindsight, this was the wrong decision to make. But the authors come from a scientific environment that is underrepresented in nutritional research and the journal aims to prioritise high quality evidence, which usually comes from clinical trials.

“These are relatively unusual in nutritional research as they can be challenging to undertake because of the numbers of participants and time needed to obtain meaningful results.”

Source: The BMJ Group

Link Between Calcium Supplements and Dementia Debunked by New Research

New research has found no evidence that calcium monotherapy increases the long-term risk for dementia.

Photo by cottonbro studio

New research from Edith Cowan University (ECU), Curtin University and the University of Western Australia has found no evidence that calcium monotherapy increases the long-term risk for dementia, helping to dispel previous concerns about its potential negative effects on brain health in older women.

This study, which leveraged outcomes from prior research that provided calcium supplements or a placebo to 1460 older women over a five-year period, found that the supplement did not increase the long-term risk of dementia.

“Calcium supplements are often recommended to prevent or manage osteoporosis,” said ECU PhD student Ms Negar Ghasemifard.

Around 20 per cent of women over the age of 70 are affected by osteoporosis and calcium supplementation is widely recommended as a preventative measure against fracture.

“Previous research has raised concerns around the impacts that calcium supplements could have on cognitive health, particularly dementia. Results from our study provides reassurance to patients and clinicians regarding the safety of calcium supplements in the context of dementia risk for older women,” Ms Ghasemifard said.

ECU Senior Research Fellow Dr Marc Sim noted that when the analysis was adjusted for supplement compliance, a range of lifestyle factors, including dietary calcium intake and genetic risk, the results remained unchanged.

“Previous research suggesting potential links between calcium supplement use and the risk for dementia was purely observational in nature. Our research, in comparison, consisted of a post-hoc analysis from a 5-year double-blind, placebo controlled randomised clinical trial on calcium supplements to prevent fracture. Whilst our study is still epidemiology, its design does reduce the likelihood of unmeasured confounding”

“Some 730 older women were given calcium supplements over five years, and a further 730 were given placebo. This study design offers more accurate data on dosage and duration, and we had a long follow-up period of 14.5 years, which strengthens our results,” Dr Sim said.

While these findings may alleviate concerns regarding calcium supplementation and all-cause dementia risk in older women, particularly after the age of 80 years, Professor Simon Laws, Director of ECU’s Centre for Precision Health, said further research was required.

“Whether this extrapolates to other demographics, such as men or even women commencing supplementation earlier in life, remains unknown. To confirm the current findings, particularly regarding brain health, and to address these population gaps, future clinical trials of calcium supplements, with or without vitamin D, would need to be undertaken. These should include specific and robust assessments of brain health as the primary outcome measures.”

Curtin University’s Professor Blossom Stephan, Director of the Dementia Centre of Excellence and a Dementia Australia Honorary Medical Advisor said the research highlighted a very important finding that provides reassurance to clinicians and patients about the long-term safety of calcium supplementation.

“Given calcium’s critical role in multiple physiological functions, including bone health, these results provide reassurance that long-term calcium supplementation did not increase dementia risk in older women,” she said.

Source: Edith Cowan University

‘Synbiotic’ Offers Superior Anti-inflammatory Benefits to Omega-3 or Prebiotic Alone

Photo by Aleksander Saks on Unsplash

A new study, led by experts at the University of Nottingham, has found that combining certain types of dietary supplements is more effective than single prebiotics or omega-3 in supporting immune and metabolic health, which could lower the risk of conditions linked to chronic inflammation.

The findings of the study, which are published in the Journal of Translational Medicineshow that a synbiotic – a combination of naturally fermented kefir and a diverse prebiotic fibre mix – produces the most powerful anti-inflammatory effects among the three common dietary supplements tested.

The kefir and prebiotic mix contains a mx of naturally occurring probiotic bacteria and yeasts, which form during the traditional fermentation of goat’s milk with live kefir grains. These grains are living cultures that house dozens of beneficial microbial species.

When you combine kefir (rich in live beneficial microbes) with a diverse prebiotic fibre (which feeds them), there is a synbiotic effect – the fibre nourishes the microbes, helping them thrive and produce beneficial metabolites like butyrate, which has anti-inflammatory and immune-modulating effects throughout the body.

Over six weeks, healthy participants taking the synbiotic saw the broadest reduction in inflammation-related proteins compared to those taking omega-3 or fibre alone. The findings suggest that pairing beneficial microbes with prebiotic fibre could help support immune and metabolic health more effectively than single supplements.

Systemic inflammatory markers are signals in the blood that show how much inflammation is happening throughout the body, not just in one specific area like the gut or an infection. The findings of the study showed that the participants’ overall levels of inflammation across their whole body went down, suggesting an improvement in general immune balance and lower risk for conditions linked to chronic inflammation (like heart disease or other metabolic conditions).

The next stage of the research would be to test the supplements on people with certain conditions to see the effectiveness.

The study was led by Dr Amrita Vijay in the School of Medicine at the University of Nottingham. 

Our study shows that while all three dietary approaches reduced inflammation, the synbiotic – combining fermented kefir with a diverse prebiotic fibre mix – had the most powerful and wide-ranging effects. This suggests that the interaction between beneficial microbes and dietary fibre may be key to supporting immune balance and metabolic health.

Dr Amrita Vijay

Source: University of Nottingham

Certain Fatty Acids can ‘Supercharge’ T-Cells’ Antitumour Immunity

A research team at the LKS Faculty of Medicine of the University of Hong Kong (HKUMed) discovered that certain dietary fatty acids can supercharge the human immune system’s ability to fight cancer. The team found that a healthy fatty acid found in olive oil and nuts, called oleic acid (OA), enhances the power of immune γδ-T cells, specialised cells known for their cancer-fighting properties.

Conversely, they found that another fatty acid, called palmitic acid (PA), commonly found in palm oil and fatty meats, diminishes the ability of these immune cells to attack tumours. This groundbreaking study, published in the academic journal Signal Transduction and Targeted Therapy, offers an innovative approach using dietary OA supplementation to strengthen the antitumour immunity of γδ-T cells.

Dietary fatty acids and cancer immunotherapy

Dietary fatty acids are essential for health, helping with growth and body functions. They may also play a role in cancer prevention and treatment, but understanding how they affect cancer is challenging because of the complexity of people’s diets and the lack of detailed studies. Recently, scientists have learned that fatty acids can influence the immune system, especially in how it fights cancer. Specialised immune cells, called γδ-T cells, are particularly good at attacking tumours. These cells, once activated, have helped some lung and liver cancer patients live longer. However, this therapy is not effective for all patients, partly because the variation of the metabolic status, such as fatty acid metabolism, can influence its efficacy in the patients.

Oleic acid may improve cancer treatment outcomes

The research team identified a correlation between PA and OA levels and the efficacy of cancer therapies. ‘Our research suggests that dietary fatty acid supplementation, particularly with foods rich in OA, such as olive oil and avocados, could enhance γδ-T cell immunosurveillance, leading to more effective cancer treatments,’ said Professor Tu Wenwei from the Department of Paediatrics and Adolescent Medicine, School of Clinical Medicine, HKUMed, who led the study.

The team also discovered that another fatty acid, called PA, can weaken these immune cells and how OA can counteract this. ‘The results indicate that cancer patients should avoid PA and consider OA supplementation in their diets to improve clinical outcomes of γδ-T cell-based cancer therapies,’ added Professor Tu.

Significant impact from simple dietary changes

Professor Tu said, ‘This study is the first to show that the fatty acids we eat can directly affect how well our immune cells fight cancer.’ It reveals how PA can harm these cells and how OA helps them through a specific process involving a protein called IFNγ. By analysing blood samples, the researchers confirmed that the levels of these fatty acids are linked to the outcome of cancer immunotherapy.

‘For cancer patients, this discovery suggests simple changes, like eating more foods rich in OA (such as olive oil, avocados and nuts) and cutting back on PA (found in processed foods, palm oil and fatty meats), could improve the effectiveness of cancer treatments. The study also points to novel strategies, like combining dietary changes with specific drugs to further boost the immune system,’ added Professor Tu.

This study demonstrates that personalised nutrition may serve as an effective strategy to enhance immune function and support cancer treatment. It also suggests that new drugs targeting the processes affected by these fatty acids could enhance the power of γδ-T cell therapies. By integrating nutritional interventions with immunotherapy, this discovery could help more cancer patients achieve better outcomes.

Source: University of Hong Kong

Vitamin D2 Supplements May Actually Lower Vitamin D3 Levels

Photo by Michele Blackwell on Unsplash

Taking vitamin D2 might lower the body’s levels of the more efficient form of vitamin D, vitamin D3, according to new research from the University of Surrey, John Innes Centre and Quadram Institute Bioscience. 

Many people take vitamin D supplements to support their bone and immune health and meet the UK government recommendation of 10 micrograms (µg) each day, especially during the winter months. 

There are two forms of vitamin D supplements available: vitamin D2 and vitamin D3. Researchers have found that taking vitamin D2 supplements can lead to a drop in the body’s concentration of vitamin D3, which is the form our bodies naturally produce from sunlight and use most effectively to raise overall vitamin D levels.  

The study, published in Nutrition Reviews, analysed data from randomised controlled trials and found that vitamin D2 supplementation resulted in a reduction in vitamin D3 levels compared to those not taking a vitamin D2 supplement. In many of the studies, the vitamin D3 levels went lower than in the control group. 

Vitamin D supplements are important, especially between October and March, when our bodies cannot make vitamin D from sunlight in the UK. However, we discovered that vitamin D2 supplements can actually decrease levels of vitamin D3 in the body, which is a previously unknown effect of taking these supplements. This study suggests that subject to personal considerations, vitamin D3 supplements may be more beneficial for most individuals over vitamin D2. 

Emily Brown, PhD Research Fellow and Lead Researcher of the study from the University of Surrey’s Nutrition, Exercise, Chronobiology & Sleep Discipline

This research supports a previous study published in Frontiers in Immunology, led by Professor Colin Smith from the University of Surrey, which suggests that vitamin D2 and D3 do not have identical roles in supporting immune function. Vitamin D3 has a modifying effect on the immune system that could fortify the body against viral and bacterial diseases

We have shown that vitamin D3, but not vitamin D2, appears to stimulate the type I interferon signalling system in the body – a key part of the immune system that provides a first line of defence against bacteria and viruses. Thus, a healthy vitamin D3 status may help prevent viruses and bacteria from gaining a foothold in the body.

Professor Colin Smith, University of Surrey

Further research into the different functionalities of vitamin D2 and D3 should be a priority in deciding whether vitamin D3 should be the first-line choice of vitamin D supplement, subject to individual requirements. 

Source: University of Surrey

Sugary Drinks May Increase Risk of Metastasis in Advanced Colorectal Cancer

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A new study from researchers at The University of Texas MD Anderson Cancer Center shows that the glucose-fructose mix found in sugary drinks directly fuels metastasis in preclinical models of advanced colorectal cancer. The study was published in Nature Metabolism.

A research team led by Jihye Yun, PhD, assistant professor of Genetics, studied how sugary drinks may affect late-stage colorectal cancer. Using laboratory cancer models, they compared the effects of the glucose-fructose mix found in most sugary drinks with those of glucose or fructose alone. Only the sugar mix made cancer cells more mobile, leading to faster spread to the liver – the most common site of colorectal cancer metastasis.

The sugar mix activated an enzyme called sorbitol dehydrogenase (SORD), which boosts glucose metabolism and triggers the cholesterol pathway, ultimately driving metastasis. This is the same pathway targeted by statins, common heart drugs that inhibit cholesterol production. Blocking SORD slowed metastasis, even with the sugar mix present. These findings suggest that targeting SORD could also offer an opportunity to block metastasis.

“Our findings highlight that daily diet matters not only for cancer risk but also for how the disease progresses once it has developed,” Yun said. “While these findings need further investigation, they suggest that reducing sugary drinks, targeting SORD or repurposing statins may benefit patients with colorectal cancer.”

The Yun Laboratory is interested in studying how diet affects the intestine and cancer development, and they have made important discoveries on the impacts of sugary drinks on colorectal cancer.

Sugar has long been indirectly linked to an increase in cancer risk through obesity. However, a previous study by Yun’s lab challenged that view, showing that even moderate intake of sugary drinks directly fuelled tumour growth in early-stage colorectal cancer, independent of obesity. The current study was done to determine how sugary drinks may impact later-stage disease.

While this study needs further clinical investigation, the results suggest that reducing sugary drinks and targeting the SORD enzyme may offer opportunities to reduce colorectal cancer metastasis. Additional studies are warranted to confirm these results outside of preclinical models.

Further, Yun explained it may be worthwhile to consider revisions to current dietary recommendations to reduce sugary drink consumption in this patient population. To meet nutritional needs, many patients with cancer are encouraged to have nutritional supplement drinks and concentrated juices that contain high glucose and fructose content.

Source: The University of Texas MD Anderson Cancer Center