Diets often recommend avoiding nuts as they contain a large amount of fat even though they are high in protein and fibre. Now, a large study published in the journal Obesity demonstrated that including almonds in an energy restricted diet not only helped participants to lose weight, but also improved their cardiometabolic health.
Examining the effects of energy restricted diets supplemented with Californian almonds or with carbohydrate- rich snacks, researchers found that both diets successfully reduced body weight by about 7kg.
Globally, more than 1.9 billion adults are overweight (650 million with obesity). Two in three people (approximately 12.5 million adults) are overweight or have obesity, as do one in every two South Africans.
UniSA researcher Dr Sharayah Carter says the study demonstrates how nuts can support a healthy diet for weight management and cardiometabolic health.
“Nuts, like almonds, are a great snack. They’re high in protein, fibre, and packed with vitamins and minerals, but they also have a high fat content which people can associate with increased body weight,” Dr Carter says.
“Nuts contain unsaturated fats – or healthy fats – which can improve blood cholesterol levels, ease inflammation, and contribute to a healthy heart.
“In this study we examined the effects of an almond-supplemented diet with a nut-free diet to identify any influence on weight and cardiometabolic outcomes.
“Both the nut and nut free diets resulted in approximately 9.3% reduction in body weight over the trial.
“Yet the almond-supplemented diets also demonstrated statistically significant changes in some highly atherogenic lipoprotein subfractions, which may lead to improved cardiometabolic health in the longer term.
“Additionally, nuts have the added benefit of making you feel fuller for longer, which is always a pro when you’re trying to manage your weight.”
The study, funded by the Almond Board of California, had 106 participants complete a 9-month eating program (a three-month energy-restricted diet for weight loss in Phase 1, followed by Phase 2, a six-month energy-controlled diet for weight maintenance). In both phases, 15% of participants’ energy intake comprised unsalted whole almonds with skins (for the nut diet) or 15% carbohydrate-rich snacks – such as rice crackers or baked cereal bars (for the nut-free diet).
Reductions occurred in fasting glucose (−0.2mmol/L), insulin (−8.1pmol/L), blood pressure (−4.9 mmHg systolic, −5.0mmHg diastolic), total cholesterol (−0.3 mmol/L), low-density lipoprotein (LDL) (−0.2mmol/L), very low-density lipoprotein (−0.1mmol/L), and triglycerides (−0.3mmol/L), and high-density lipoprotein increased (0.1mmol/L) by the end of Phase 2 in both groups.
New research suggests that extreme dietary habits involving carbohydrates and fats affect life expectancy. Results published in The Journal of Nutritionshow that a low carbohydrate intake in men and a high carbohydrate intake in women are associated with a higher risk of all-cause and cancer-related mortality and that women with higher fat intake may have a lower risk of all-cause mortality. Their findings suggest that people should pursue a balanced diet rather than heavily restricting their carbohydrate or fat intake.
While low-carbohydrate and low-fat diets are becoming popular as a way to promote weight loss and improve blood glucose levels, their long-term effects on life expectancy are less clear. Interestingly, recent studies conducted in Western countries suggest that extreme dietary habits for carbohydrates and fats are associated with a higher risk of mortality. However, few studies have explored these associations in East Asian populations, including Japanese individuals who typically have relatively low fat and high-carbohydrate dietary intakes.
Researchers from Nagoya University Graduate School of Medicine in Japan led by Dr Takashi Tamura conducted a follow-up survey over a period of 9 years with 81 333 Japanese people (34,893 men and 46 440 women) to evaluate the association between carbohydrate and fat intakes and the risk of mortality. Daily dietary intakes of carbohydrates, fats, and total energy were estimated using a food frequency questionnaire and calculated as a percentage of total energy intake for carbohydrates and fats. Carbohydrate intake quality (ie, refined compared with minimally processed carbohydrate intake) and fat intake quality (ie, saturated compared with unsaturated fat intake) were also assessed to examine the impact of food quality on the association with mortality.
They found that men who consumed less than 40% of their total energy from carbohydrates experienced significantly higher risks of all-cause and cancer-related mortality. The trend was observed regardless of whether refined or minimally processed carbohydrate were considered. On the other hand, among women with 5 years or longer of follow-up, those with a high carbohydrate intake of more than 65% had a higher risk of all-cause mortality. No clear association was observed between refined or minimally processed carbohydrate intake and the risk of mortality in women.
For fats, men with a high fat intake of more than 35% of their total energy from fats had a higher risk of cancer-related mortality. They also found that a low intake of unsaturated fat in men was associated with a higher risk of all-cause and cancer-related mortality. In contrast, total fat intake and saturated fat intake in women showed an inverse association with the risk of all-cause and cancer-related mortality. They concluded that this finding does not support the idea that high fat intake is detrimental to longevity in women.
“The finding that saturated fat intake was inversely associated with the risk of mortality only in women might partially explain the differences in the associations between the sexes,” Dr Tamura stated. “Alternatively, components other than fat in the food sources of fat may be responsible for the observed inverse association between fat intake and mortality in women.”
This study is extremely important because restricting carbohydrates and fats, such as extremely low-carbohydrate and low-fat diets, are now popular dieting strategies aimed at improving health, including the management of metabolic syndrome. However, this study shows that low-carbohydrate and low-fat diets may not be the healthiest strategy for promoting longevity, as their short-term benefits could potentially be outweighed by long-term risk.
Overall, an unfavourable association with mortality was observed for low-carbohydrate intake in men and for high carbohydrate intake in women, whereas high fat intake could be associated with a lower mortality risk in women. The findings suggest that individuals should carefully consider how to balance their diet and ensure that they are taking in energy from a variety of food sources, while avoiding extremes.
Scanning electron micrograph of red blood cells, T cells (orange) and platelets (green). Source: Wikimedia CC0
Aside from transfusions, there currently is no way to boost people’s platelet counts, which can drop for reasons such as chemotherapy, leaving them at risk for uncontrolled bleeding. But new research published in Nature Cardiovascular Research suggests that there could be a simple alternative: a dietary change in type of fat intake could raise platelet counts in people with low levels.
A study led by Kellie Machlus, PhD, and Maria Barrachina, PhD at Boston Children’s Hospital found that they could raise platelet counts in mice by feeding them polyunsaturated fatty acids (PUFAs) like those found in the Mediterranean diet. In contrast, mice fed a diet high in saturated fatty acids had decreased platelet counts.
“We were honestly surprised at how profound the effects were,” says Machlus, whose lab focuses on studying platelets and their precursor cells, megakaryocytes, and ways to get the body to increase platelet production.
But equally interesting is the apparent reason for the dietary effect.
“What brought me to the idea of diet is that megakaryocytes make these long extensions from their membrane when they form platelets,” Machlus says. “We thought the membrane must have an unusual composition to make it so fluid.”
A fluid megakaryocyte membrane
No one had studied megakaryocyte membranes before, perhaps because megakaryocytes are in the bone marrow and hard to access. Machlus, Barrachina, and their colleagues decided to comprehensively assess the membranes’ fat content with lipidomics.
“We found that PUFAs are enriched in megakaryocytes, especially right before they begin making platelets,” says Machlus. “We think they provide the fluidity necessary for the membrane to move and reshape.”
In culture, the megakaryocytes with higher amounts of PUFAs in their membrane made more platelets. When the cells were instead supplied with saturated fats as their lipid source, platelet production declined. The same thing happened when the team added compounds to inhibit uptake of PUFAs from the blood.
The researchers also identified one of the receptors on megakaryocytes that’s responsible for taking up PUFAs from blood: CD36. When they deleted the gene for CD36 in their mouse model, the animals had low platelet counts.
Serendipitously, the researchers were able to connect the dots to humans. Through a colleague in the U.K., they identified a family in which several members had a mutation in the CD36 gene. Those affected had low platelet counts and, in the mother’s case, bleeding episodes.
An olive oil intervention?
Intrigued by their findings, Barrachina hopes to extend the study by collaborating with a team in her native Spain. The team is studying dietary interventions for cardiovascular disease, including the Mediterranean diet.
“We want to look at platelets from these patients,” she says. She thinks that platelets with more saturated fatty acids in their membranes might be in a more activated state that could lead them to aggregate and form blood clots.
While Machlus thinks it may be worth encouraging patients with thrombocytopenia to consume more olive oil to increase PUFA levels, she recognises that a drug treatment may be more practical.
“Our next steps are to find out the enzymes that create PUFAs,” she says. “Maybe we can target them to make more platelets.”
Smoothies can be a tasty and convenient way to get the important fruits and vegetables needed for a healthy diet. But is a banana and blueberry smoothie the best combo? Researchers at the University of California, Davis, suggest that blending certain ingredients in smoothies can influence whether your body is getting a nutritional boost.
The study, published today in the journal Food and Function, used smoothies to test how various levels of polyphenol oxidase (PPO), an enzyme in many fruits and vegetables, affects the levels of flavanols in food to be absorbed by the body. Flavanols are a group of bioactive compounds that are good for your heart and cognitive health and are naturally found in apples, pears, blueberries, blackberries, grapes and cocoa – common smoothie ingredients.
“We sought to understand, on a very practical level, how a common food and food preparation like a banana-based smoothie could affect the availability of flavanols to be absorbed after intake,” said lead author Javier Ottaviani, director of the Core Laboratory of Mars Edge, which is part of Mars, Inc., and an adjunct researcher with the UC Davis Department of Nutrition. Mars Inc. provided the grant for this study as part of its research into flavonols in cocoa.
When peeled or sliced, PPO causes banana or apple to turn brown, The browning occurs when food with PPO is exposed to air, cut or bruised. The researchers wanted to know whether consuming freshly prepared smoothies made with different PPO-containing fruits impacted the amount of flavanols available to the body.
Bananas versus berries
The researchers had participants drink a smoothie made with banana, which has naturally high PPO activity, and a smoothie made with mixed berries, which have naturally low PPO activity. Participants also took a flavanol capsule as a control. Blood and urine samples were analysed to measure how much flavanols were present in the body after ingesting the smoothie samples and capsule. The researchers found that those who drank the banana smoothie had 84% lower levels of flavanols in their body compared to the control.
“We were really surprised to see how quickly adding a single banana decreased the level of flavanols in the smoothie and the levels of flavanol absorbed in the body,” Ottaviani said. “This highlights how food preparation and combinations can affect the absorption of dietary compounds in foods.”
Last year, the Academy of Nutrition and Dietetics issued a dietary recommendation, advising people to consume 400 to 600 milligrams of flavanols daily for cardiometabolic health. Ottaviani said for people who are trying to consume those flavanols, they should consider preparing smoothies by combining flavanol-rich fruits like berries with other ingredients that also have a low PPO activity like pineapple, oranges, mango or yogurt.
He also said bananas remain a great fruit to be eaten or consumed in smoothies. For those who want to consume smoothies with bananas, or other high PPO activity fruits and vegetables such as beet greens, the suggestion is to not combine them with flavanol-rich fruits such as berries, grapes and cocoa.
The findings of this study could spur future research into how other foods are prepared and the effects on flavanols, for example, Ottaviani said tea is a major dietary source of flavanols and depending on how it is prepared, a different amount of flavanols would be available for absorption.
“This is certainly an area that deserves more attention in the field of polyphenols and bioactive compounds in general,” said Ottaviani.
Jodi Ensunsa, Reedmond Fong, Jennifer Kimball and Alan Crozier, all affiliated with the UC Davis Department of Nutrition and researchers affiliated with the UC Davis Department of Internal Medicine, University of Reading, King Saud University and Mars, Inc. contributed to the research.
The study was funded by a research grant from Mars, Inc., which collaborates with researchers to study potential benefits of cocoa flavanols for human health.
Researchers at the Babraham Institute are proposing an alternative link between diet and ageing based on studies in yeast. In a study using yeast, a useful model organism to study ageing, researchers showed that a ‘healthier’ galactose diet in early life led to reduced senescence in those cells. The findings, published in PLOS Biology, suggest that dietary makeup at a young age may have a long-lasting impact on health throughout the lifespan.
Dr Jon Houseley and his team have published their experiments, showing that healthy ageing is achievable through dietary change without restriction by potentially optimising diet, and that ill-health is not an inevitable part of the ageing process.
Scientists have long known that caloric restriction improves health in later life and may even extend life. However, studies in mice show that caloric restriction really needs to be maintained throughout life to achieve this impact, and the health benefits disappear when a normal diet is resumed. Dr Houseley’s new research conducted in yeast suggests an alternative to calorie restriction can lead to improved health through the lifecycle.
“We show that diet in early life can switch yeast onto a healthier trajectory. By giving yeast a different diet without restricting calories we were able to suppress senescence, when cells no longer divide, and loss of fitness in aged cells.” Said Dr Dorottya Horkai, lead researcher on the study.
Rather than growing yeast on their usual glucose-rich diet, the researchers swapped their diet to galactose and observed that many molecular changes which normally accompany ageing did not occur. The cells grown on galactose remained just as fit as young cells even late in life, despite not living any longer, showing that the period of ill-health towards the end of life was dramatically reduced.
“Crucially, the dietary change only works when cells are young, and actually diet makes little difference in old yeast. It is hard to translate what youth means between yeast and humans, but all these studies point to the same trend – to live a long and healthy life, a healthy diet from an early age makes a difference.” explains Dr Houseley.
Yeast are good model organisms for studying ageing as they share many of the same cellular machinery as animals and humans. This avenue of research in yeast helps us to seek a more achievable way to improve healthy ageing though diet compared to sustained and severe calorie restriction, although more research is needed.
Coffee is one of the world’s most popular beverages, but it also has potential health concerns, one of which is the production of foodborne toxicants such as acrylamide and furan during roasting process. A study published in Beverage Plant Research investigated ways to mitigate both contaminants in coffee by changing roasting parameters, including special procedures.
A study analysed a Vietnam Robusta grade 2 and a Brazil Arabica (unwashed) coffee with different roasting profiles (tangential, drum and hot air roasting) and roast degrees (light, medium and dark roast). Researchers accurately measured the acrylamide and furan derivative content in the samples by GC-MS. They found that acrylamide contents were highest in light roasts, and the content of furan and methylfurans were low in light roasts for both the Robusta and Arabica samples.
In addition, the study also explored the impact of special roasts, such as double roast or roasting with a sudden temperature change on acrylamide and furan content. The results showed that special roasts had no significant effect on the two contaminants. To sum up, these findings suggest that the coffee type and roasting process significantly influence the levels of these toxicants. Simultaneous mitigation of the effects of acrylamide and furan/methylfuran by changing the roasting parameters is not possible.
In conclusion, the research results show that both the type of coffee and its roasting profile have a substantial impact on the levels of acrylamide and furan, highlighting the possibility of regulating these toxicants through controlled roasting processes. However, simultaneous mitigation of these toxicants seems to be impossible. This study holds significant implications for the future of coffee production, potentially paving the way for safer and healthier consumption practices.
One of the first studies to look at the association between intake of sugar-sweetened beverages, artificially sweetened beverages, and incidence of liver cancer and chronic liver disease mortality, has found an 85% increase in liver cancer incidence between postmenopausal women who consume one sweetened drink per day and those who consume them rarely. Results from the study, which was led by Brigham and Women’s Hospital, are published in JAMA.
“To our knowledge, this is the first study to report an association between sugar sweetened beverage intake and chronic liver disease mortality,” said first author Longgang Zhao, PhD, of the Brigham’s Channing Division of Network Medicine. Zhao is a postdoctoral researcher who works with senior author Xuehong Zhang, MBBS, ScD, in the Channing Division. “Our findings, if confirmed, may pave the way to a public health strategy to reduce risk of liver disease based on data from a large and geographically diverse cohort.”
This observational study included nearly 100 000 postmenopausal women from the large, prospective Women’s Health Initiative study. Participants reported their usual soft drink, fruit drink (not including fruit juice) consumption, and then reported artificially sweetened beverage consumption after three years. Participants were followed for a median of more than 20 years. Researchers looked at self-reported liver cancer incidence and death due to chronic liver disease such as fibrosis, cirrhosis, or chronic hepatitis, which were further verified by medical records or the National Death Index.
A total of 98 786 postmenopausal women were included in the final analyses. The 6.8% of women who consumed one or more sugar-sweetened beverages daily had an 85% higher risk of liver cancer and 68% higher risk of chronic liver disease mortality compared to those who had fewer than three sugar sweetened beverages per month. No such increase was observed for consumption of artificially-sweetened beverages.
The authors note that the study was observational, and causality cannot be inferred, and relied on self-reported responses about intake, sugar content and outcomes. More studies are needed to validate this risk association and determine why the sugary drinks appeared to increase risk of liver cancer and disease. Furthermore, more research is needed to elucidate the potential mechanisms by integrating genetics, preclinical and experimental studies, and -omics data.
Artificial sweeteners have once again returned to the headlines with the WHO listing them as a possible carcinogen, Now, a long-term study on artificial sweeteners in diets published in the International Journal of Obesity has shown that, ironically, nearly all of them are linked to increased adiposity.
In the two decade long study, University of Minnesota researchers examined people’s regular dietary intake, with a focus on non-nutritive sweeteners commonly found in artificial sweeteners. They found that long-term consumption of aspartame, saccharin and diet beverages were linked to increased abdominal and intramuscular adiposity. However, the study found no significant association between the artificial sweetener sucralose and these measures of fat volume.
“This study showed that habitual, long-term intake of total and individual artificial sweetener intakes are related to greater volumes of adipose tissue, commonly known as body fat,” said Brian Steffen, PhD, MSCR, a professor in the Department of Surgery at the U of M Medical School and co-investigator on the funded grant. “This was found even after accounting for other factors, including how much a person eats or the quality of one’s diet.”
The study’s findings raise concerns about the recommendations from the American Diabetes Association and the American Heart Association that promote the replacement of added sugars with artificial sweeteners. Based on their results, the researchers recommend considering alternative approaches, as long-term artificial sweetener consumption may have potential health consequences.
“This is an especially timely study, given the World Health Organization’s recent warning of the potential health risks of aspartame,” said Lyn Steffen, PhD, MPH, a professor in the School of Public Health and principal investigator on the study. “These findings underscore the importance of finding alternatives to artificial sweeteners in foods and beverages, especially since these added sweeteners may have negative health consequences.”
The researchers say that more studies are needed to better understand the connection between artificial sweetener intake and increased body fat. Further research is warranted to explore the underlying mechanisms and gain clearer insights into how dietary habits affect metabolic health.
The draft regulations were gazetted in January and consumers had until 21 July to comment. These regulations, among other things, propose the mandatory use of new and bolder warning labels on unhealthy food which include items high in salt, sugar, saturated fats and items containing artificial sweeteners.
Community Media Trust (CMT) is a not-for-profit company, mainly focused on health and human rights and has partnered with the Healthy Living Alliance (HEALA), a coalition of organisations focused on nutrition.
In February, CMT and HEALA staged a flash mob as part of the “Less Sugar, More Life” campaign in Cape Town ahead of the Finance Minister’s Budget Speech, advocating for an increase in the sugary drinks tax. They were disappointed by the announcement that the tax would be frozen for two years.
Following a massive media campaign on the draft regulations, CMT and HEALA successfully collected thousands of submissions.
CMT’s co-director Lucilla Blankenberg said the warning labels had been tested with audiences and researchers. If you’re a diabetic shopping for food and there was a clear warning label saying, ‘high in sugar’, the consumer won’t have to spend time trying to work it out because the message is simple.
The proposed warning labels are black and white triangles and would clearly indicate when food is high in sugar, salt and fat or contains artificial sweeteners.
“The reason the food industry is fighting back is because if food has a warning label, it cannot be marketed directly to children. Which means cartoons and animation that will attract children cannot be used to market a food item that has a warning label. If a pack has a warning label they can’t make any health claims whatsoever,” said Blankenberg.
“We won’t see the results immediately, but it will happen over time, especially for the children. With warning labels, it will be easier for parents to avoid buying certain food,” said Blankenberg.
HEALA’s communications manager Zukiswa Zimela said conversations proposing front of pack warning labels started in 2016.
Zimela said research for the campaign was initially done by the University of Western Cape to determine which foods qualify to have front of pack warning labels. She said the research gave more insight into what consumers thought of the current information on packaging as well as what the new warnings should look like.
“We started the campaign in May and went to eight provinces, mainly to educate and inform communities about the importance of front of pack warning labels and the food they were eating,” said Zimela. She said they found that many consumers agreed that they did not understand the nutritional information on food packaging.
She said the food industry had used scare tactics like saying warning labels would cause job losses which was “completely untrue”.
“This is not something new, warning labels have been done in other countries like Chile, Mexico, Peru and Columbia and there has been no evidence that jobs have been lost because of it. This is just undermining the government’s plan to get people to eat better.”
Zimela said HEALA will be monitoring the responses to the regulations. “Should the regulations be implemented, we need to make sure that they are not watered down or seen as useless.”
Sugar industry warns against “demonising sugar”
The South African Sugar Association (SASA) told GroundUp it had also submitted comments on the draft regulations, and that the front of pack warning labelling system was of particular concern to the industry.
SASA executive director, Trix Trikam, said: “The objective of this system is to encourage the reduction of energy/calorie intake, saturated fat and salt to prevent obesity and non-communicable diseases.
“It is well known and there is evidence that sugar is not the sole contributor of kilojoules to the diet and should therefore not be singled out in a regrettable out-of-context manner,” he said.
He said the warning labels should not be done in a sensationalist or alarmist manner “which seeks to demonise sugar” because that would have “a significant adverse impact on the sugar industry”.
Trikman suggested that the warning labels should instead reflect the calories in a food product. “SASA is also not convinced that the perceived cut-off values for sugar is evidence-based. A possible solution to that would be to use the perceived cut-off values based on percentage of energy value and not the amount of sugar per volume of product,” said Trikam.
“The draft regulations make it mandatory for a warning symbol to be placed on the front of pack labels for foods that exceed a perceived cut-off value for sugar. In order to avoid the warning symbol for sugar, food manufacturers will seek to find ways of removing sugar from their products. This will lead to a decrease in the demand for sugar and will ultimately negatively impact the livelihoods of those dependent on the sugar industry in the deeply rural areas of KwaZulu-Natal and Mpumalanga.”
Trikam said SASA is concerned about the obesity rates in South Africa but added that the solutions should be evidence-based.
Disclosure: GroundUp was once a project of, and still has a close relationship with, Community Media Trust.
Researchers from Singapore have identified a potential dietary supplement of omega-3 that may improve recovery following acute kidney injury (AKI). The finding, published in the Journal of Lipid Research, may offer a new way to treat this serious condition, which currently has few therapies.
The study was part of a long-running research programme at Duke-NUS Medical School investigating how cells take up a specialised omega-3 lipid called LPC-DHA.
AKI affects some 13.3 million people globally each year, with a mortality rate of 20 to 50% depending on the economic status of the country and stage of the disease. One of the main causes of AKI is ischaemic reperfusion injury, which occurs when the kidney’s blood supply is restored after a period of restricted blood flow and poor oxygen delivery due to illness, injury or surgical intervention. In particular, it damages a crucial part of the kidney called the S3 proximal tubules that regulate the levels of absorption of water and soluble substances, including salts.
“AKI is a serious health problem with limited treatment options,” said Dr Randy Loke, first author of the study. “We sought to understand how these tubules repair themselves and found that the activity of the protein Mfsd2a, which transports LPC-DHA into cells, is a key factor influencing the rate of recovery of kidney function after ischaemic reperfusion injury.”
In their study, the researchers discovered that preclinical models with reduced levels of Mfsd2a showed delayed recovery, increased damage and inflammation after kidney injury. However, when these models were treated with LPC-DHA, their kidney function improved and the damage was reduced. LPC-DHA also restored the structure of the S3 proximal tubules, helping them function properly again.
“While more research is needed, the potential of LPC-DHA as a dietary supplement is exciting for future recipients who have suffered from AKI,” said senior study author Professor David Silver. “As our results suggest that LPC-DHA could become a safe and effective treatment that offers lifelong protection, its potential can help protect the kidneys and aid in recovery for these individuals.”
In the next phase, the research team plans to continue investigating the beneficial functions of LPC in the kidney and are aiming to initiate clinical testing of LPC supplements to determine their effectiveness in improving renal function and recovery following AKI in patients.
They also plan to continue their investigations of the protein Mfsd2a to learn more about its role in LPC transport and its involvement in diseases affecting other tissues and organs. Previous research by Prof Silver’s group, with collaborators from other institutions, have already highlighted the significance of the protein’s LPC-transporting activities in diseases of other organs, including the liver, lungs and brain.
