Tag: nutrition

Categories : Diet and NutritionTags :

Low Fat Diets Reduce Testosterone

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A new study has found that low fat diets decrease men’s testosterone levels by 10-15%, with important considerations for health.

Optimal testosterone levels are a crucial part of men’s health, with higher risks of heart disease, diabetes, and Alzheimer’s disease resulting from low levels of the hormone. Healthy testosterone levels are also key for men’s athletic performance, mental health, and sexual health. Clinically low testosterone rates are referred to as hypogonadism.

Men’s testosterone levels have been falling since the 1970s but low risk dietary strategies could be a useful treatment for low testosterone.

In a systematic review and meta-analysis, the researchers analysed the results of six well-controlled studies with a total of 206 participants. Men were first put on a high fat diet (40% fat), and then switched to a low fat diet (20% fat), with testosterone levels decreasing by 10-15% on average. Particularly bad were vegetarian low fat diets causing decreases in testosterone up to 26%.

Previous studies conducted in humans and mice found that high intakes of monounsaturated fats found in olive oil, avocados, and nuts may boost testosterone production. However, omega 6 polyunsaturated fats predominantly found in vegetable oils, may in fact damage the cells’ ability to produce testosterone. This is because highly unsaturated fats such as polyunsaturated fats are more prone to oxidation, causing damage to the cells.

“Low testosterone levels are linked to a higher risk of heart disease, diabetes, and Alzheimer’s disease.”

More research needs to be done in this area, said the researchers.

“Ideally, we would like to see a few more studies to confirm our results. However, these studies may never come, normally researchers want to find new results, not replicate old ones. In the meantime, men with low testosterone would be wise to avoid low fat diets.” said lead researcher Joseph Whittaker.

A controversial topic in nutritional science, dietary fibre has proponents of various diets often in stark disagreement over low fat versus low carbohydrates. Low fat diets have benefits such as reduced cholesterol levels, which should be weighed up against the potential downsides, such as decreased testosterone levels.

Traditionally, dietary guidelines have focused on limiting fat intake, with the current UK and US guidelines limiting fat intake to less than 35% of total calories. However, as more research on the benefits of high fat, low carbohydrate diets is done, this traditional view is coming under increasing scrutiny. Recent research has shown that high fat diets can decrease triglycerides, decrease blood pressure, increase HDL cholesterol (aka ‘good cholesterol’), and now it was found that it can increase testosterone levels.

Source: News-Medical.Net

Journal information: Whittaker, J & Wu, K (2021) Low-fat diets and testosterone in men: Systematic review and meta-analysis of intervention studies. The Journal of Steroid Biochemistry and Molecular Biology. doi.org/10.1016/j.jsbmb.2021.105878.

Categories : NeurologyTags :

Sugar-sweetened Drinks During Adolescence Impacts Cognition in Adulthood

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New research has shown that, in rats, daily consumption of sugar-sweetened drinks during adolescence impairs performance on a learning and memory task during adulthood. 

The researchers also demonstrated that changes in the bacteria in the gut may be the key to the sugar-induced memory impairment. Evidence in support of this comes from the observation of similar memory deficits even when the bacteria, called Parabacteroides, were experimentally enriched in the guts of animals that had never consumed sugar.

“Early life sugar increased Parabacteroides levels, and the higher the levels of Parabacteroides, the worse the animals did in the task,” said first author Emily Noble, assistant professor, College of Family and Consumer Sciences, University of Georgia. “We found that the bacteria alone was sufficient to impair memory in the same way as sugar, but it also impaired other types of memory functions as well.”

Data from the Centers for Disease Control and Prevention show American children between the ages 9-18 exceed the recommendation of limiting added sugars to less than 10 percent of calories per day, with the bulk of the calories coming from sugar-sweetened beverages.

Since the hippocampus is still developing into late adolescence and plays a role in a variety of cognitive functions, researchers sought to understand more about its susceptibility to a high-sugar diet via gut microbiota.

Juvenile rats were given their normal chow and an 11% sugar solution, comparable to commercially available sugar-sweetened beverages. Researchers then had the rats perform a hippocampus-dependent memory task designed to measure episodic contextual memory, or remembering the context where they had seen a familiar object before.

“We found that rats that consumed sugar in early life had an impaired capacity to discriminate that an object was novel to a specific context, a task the rats that were not given sugar were able to do,” Prof Noble said.

A second memory task measured basic recognition memory, a hippocampal-independent memory function that involves the animals’ ability to recognise something they had seen previously. Sugar had no effect on the animals’ recognition memory.

“Early life sugar consumption seems to selectively impair their hippocampal learning and memory,” Prof Noble said.

Further analysis revealed that high sugar consumption led to elevated levels of Parabacteroides in the gut microbiome, the more than 100 trillion microorganisms in the gastrointestinal tract that play a role in human health and disease.

To determine the mechanism by which bacteria impacted memory and learning, researchers experimentally increased levels of Parabacteroides in the microbiome of rats that had never consumed sugar. Those animals showed impairments in both hippocampal dependent and hippocampal-independent memory tasks.

“(The bacteria) induced some cognitive deficits on its own,” Prof Noble said.

Future research is needed to better identify these gut-brain signaling specific pathways.

“The question now is how do these populations of bacteria in the gut alter the development of the brain?” Prof Noble said. “Identifying how the bacteria in the gut are impacting brain development will tell us about what sort of internal environment the brain needs in order to grow in a healthy way.”

Source: News-Medical.Net

Journal information: Noble, E. E., et al. (2021) Gut microbial taxa elevated by dietary sugar disrupt memory function. Translational Psychiatry. doi.org/10.1038/s41398-021-01309-7.

Categories : Environmental EffectsTags :

Edible Food Film Packaging Developed as Alternative to Plastic

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Researchers from India and Russia have created edible food films for packaging fruits, vegetables, poultry, meat, and seafood. 

These films are made up of natural ingredients, and as such are safe for health and the environment. In addition, these films are water-soluble and dissolve by almost 90% over 24 hours. A description of their research and the results of their experiments are published in the Journal of Food Engineering.

Using such films would help to reduce the problem of microplastics, micrometre-scale fragments of plastic which have been detected in human stools as well as inhaled through the lungs.Chemicals such BPAs, phthalates and flame retardants, as well as heavy metals included in plastics are of concern to human health. The increased surface area/volume ratio of microplastics in combination with their hydrophobicity, results in a high affinity with a broad range of hydrophobic and persistent organic pollutants, antibiotics, and heavy metals that could be introduced into the human body through the uptake of microplastics.

“We have created three types of food films based on the well-known naturally occurring seaweed biopolymer sodium alginate. Its molecules have film-forming properties. Sodium alginate is an auspicious carbohydrate macromolecule that has the potential film-forming properties upon hydrolysis and abundantly existed in cell walls as a mixture of various salts. The greatest advantage of sodium alginate is that it performs as liquid-gel in an aqueous medium.”

Rammohan Aluru, Study Co-Author and Senior Researcher of Organic Synthesis Laboratory, Ural Federal University

The researchers cross-linked alginate molecules with a natural antioxidant ferulic acid, resulting in a strong and homogeneous film that is more rigid and prolongs the life of the products. However, being able to produce edible, naturally sourced films also has other benefits.

“Food stays fresh longer due to the antioxidant components that slow down the oxidation processes,” said Grigory Zyryanov, professor of the Department of Organic and Biomolecular Chemistry at Ural Federal University. “In addition, we can add to the films natural antiviral agents that will also extend the shelf life of food. Garlic, turmeric, and ginger contain compounds that may prevent the spread of the viruses.”

No special equipment for the production of films is required, the authors claim, and can be scaled up to an industrial scale by manufacturers of  food products and films.

“It can also be produced at a polymer production plant. The only condition is that it must meet the standards that apply to food production. And if an inexhaustible source of algae the ocean is nearby it will be quite simple to create such films,” said Prof Zyryanov.

Source: News-Medical.Net

Journal information: Yerramathia, B. B., et al. (2021) Structural studies and bioactivity of sodium alginate edible films fabricated through ferulic acid crosslinking mechanism. Journal of Food Engineering. doi.org/10.1016/j.jfoodeng.2021.110566.

Categories : Diet and NutritionTags :

Sugar Tax Lacks Teeth in Spanish Study

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A study on the impact of a tax on fizzy drinks and other products with a high sugar content showed that there was little modification of consumer purchasing and consumption habits.

A sugar-sweetened beverage (SSB) tax was introduced in the Spanish region of Catalonia in May 2017.

“In response to rising levels of obesity and the serious and significant negative effects this is having for individuals, their families and wider healthcare systems, over the past five years there has been growing interest in the potential effectiveness of sugar taxes,” said lead researcher Dr Eleonora Fichera at the Department of Economics, University of Bath.

To find out how the sugar tax affected purchasing habits, the researchers used customer store card data from a chain of Spanish supermarkets.

The SSB tax resulted in an increase in the price of a one litre bottle of Fanta, Sprite or Seven Up! from €1.02 to €1.18. The tax also spurred reformulation, whereby drinks producers have created and marketed new products with greatly reduced overall sugar content (such as Coke Zero).

The overall impact was tiny, however – a mere 2.2% reduction in average calories per consumer.

“By analysing the effect of a tiered tax system for sugar-sweetened beverages in Catalonia and by comparing its impact with the rest of Spain (where a tax was not introduced) our results provide important evidence to policymakers keen to explore the potential effectiveness of this approach.

“And whilst our results demonstrate some impact in shifting behaviors towards products lower in sugar, this effect is modest at best. If these taxes are to be more effective, they need to be more visible at the checkout so that consumers become increasingly aware of the added cost of their high-sugar choices. This requires that the tax is more specific too, ensuring producers are forced to pass the tax through to consumers. Although more than 20% of the Catalan tax was passed through to consumers, not all of it was, making the tax less impactful,” concluded Dr Fichera. 

Source: News-Medical.Net

Journal information: Fichera, E., et al. (2021) How do consumers respond to “sin taxes”? New evidence from a tax on sugary drinks. Social Science & Medicine. doi.org/10.1016/j.socscimed.2021.113799.

Categories : Diet and NutritionTags :

Researchers Lower Salt in Parmigiano Reggiano But Keep Flavour

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Aged cheeses like Parmigiano Reggiano are prized for their strong, sharp flavours, but their production process creates a high salt content. Now, researchers have come up with a new process that reduces the salt content, a boon for people who have to manage their salt content, such as those with hypertension.

In the production process, aged cheeses are either coated in wax or submerged in brine for a number of weeks to create a rind. Parmigiano Reggiano is produced only in certain Italian provinces, and is subject to strict regulations. Made from skimmed cow’s milk, it is aged for at least one year and is lactose free. The flavours come from conversion of milk compounds during the ripening process, in which salt plays a role by hardening the cheese and regulating microbe and enzyme activity. Parmigiano Reggiano has a sodium content of 650mg per 100g. Reducing sodium in the diet reduces hypertension and also cardiovascular disease mortality and morbidity.

A key chemical process is lipolysis, where triglycerides from milk break down into free fatty acids and diacylglycerides. Free fatty acids add to the taste of the cheese and also serve as precursors to other flavour molecules. Lipolysis also takes place in the body when adipose triglycerides are broken down for energy.

To see if salt content could be reduced without compromising flavour, the researchers submerged wheels of the cheese in brine for 18 days or a shorter 12 day period before a 15 month ripening period. Salt content was 9% lower in the cheese brined for a shorter time. The researchers were surprised to find no difference in the moisture level, cholesterol, and total fat in the two sets of cheeses.

No major variations in compounds involved in the flavour profile were seen, as most of the free fatty acids overlapped in concentration ranges.

Yet in the cheeses with the shorter brining time, overall, the total free fatty acids and the total diacylglycerides concentration ranges were 260% and 100% higher, respectively, than the traditionally brined version. It is possible that the lower salt to moisture ratio made more water available for lipolysis reactions and more rapid enzymatic triglycerides breakdown. The cheese still needs to be assessed for texture.

Source: News-Medical.Net

Categories : Cardiovascular Disease Diet and NutritionTags :

High GI Carbohydrates Raise CVD Risk Across Countries

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A multinational study has shown that high consumption of high glycaemic index foods increases the risk of cardiovascular disease (CVD) events such as stroke or heart disease, regardless of pre-existing CVD.

The study examined low-, middle- and high-income countries, beginning in 2006, with a median follow-up of 9.5 years. Data was used from nearly 120 000 participants.

The glycaemic index was first introduced in the 1970s to compare the rise of blood glucose from a given carbohydrate food in a patient in comparison to their blood glucose curve from the same patient ingesting glucose. This ranges from 20 for fructose to 100 for barley. In comparison to individuals eating low glycaemic index foods, those eating high glycaemic index foods had a greater risk of CVD events (51%) if there was pre-existing CVD, and even without CVD (21%). 

The highest glycaemic index foods were eaten in China, followed by Africa and Southeast Asia. The highest glycaemic loads were seen in Southeast Asia, followed by Africa and China. Glycaemic load is a better measure of a food’s effect on blood sugar taking into account how quickly it enters the bloodstream and how much glucose can be delivered.

There was less of an effect seen with glycaemic load only those with preexisting CVD showed an association between high glycaemic load diets and patient outcomes.

The participants were given a questionnaire, breaking foods down into seven categories based on glycaemic load and frequency, with a number of options each.

The broad geographic and economic scope of this study enabled the investigation of glycaemic index and load across a wide range of diets that would not be possible if it were restricted to sampling only Western-style diets.

“As expected, a higher glycaemic index was associated with an increased risk of adverse effects among the participants with a higher BMI, as reported previously,” the researchers wrote. “Although the glycaemic index of foods is independent of glucose-tolerance status, the overall postprandial glycaemic response to diet increases as the BMI increases.”

The authors acknowledge that economic development may have altered the mix of diets sampled over time, leading to an overestimation of glycaemic foods in China, for example. The findings nonetheless have important implications for primary and secondary prevention of CVD.

Source: MedPage Today

Journal information: Jenkins DJA, et al “Glycemic index, glycemic load, and cardiovascular disease and mortality” N Engl J Med 2021; DOI: 10.1056/NEJMoa2007123.

Categories : Diet and Nutrition General InterestTags :

Health Experts Call for a Sugar Tax Increase to 20%

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In advance of Finance Minister Tito Mboweni’s annual budget presentation on 24 February, health specialists have been calling for an increase in the health promotion levy from 11% to 20%. 

The health promotion levy (or ‘sugar tax’) was put into effect in April 2018, and imposes an 11% tax on sugar sweetened beverages. Specialists called for an increase in this tax on Tuesday at a webinar rub by the Healthy Living Alliance (Heala), saying that this was a prudent time to do it because the health sector is currently battling the COVID pandemic.

Most people hospitalised with COVID in SA have comorbidities such as diabetes and hypertension, said Karen Hofman, director of the Wits Centre for Health Economics and Decision Science (Priceless SA). Sugar, especially in liquid form, is a risk factor for obesity, diabetes, hypertension, cardiovascular disease, a number of common cancers and dental decay. She added that had those comorbidities had been prevented, the country could have been in a much better position.

Hofman said that people think they have “control over what [they] are eating and drinking”, but in fact don’t, having been heavily influenced by their environment from an early age. For the tax to have any effect, it should be increased to 20%, based on the World Health Organization and other health experts’ recommendations.

Heala head, Lawrence Mbalati, said the sugar tax had created R5.4-billion for the government within its first two years. This would have been enough to finance South Africa’s downpayment for COVID vaccines from the Covax facility almost 20 times over, in spite of its minimal contribution to the overall budget. 

A doubling of the sugar tax would net an additional R2 billion to help fight COVID, Mbalati said.

“This is a watershed moment for the country,” Mbalati continued. “Government revenues are under immense pressure and funding the fight against Covid-19, including vaccines, remains critical.”

Hofman said that research in other countries with a sugar tax had shown a fall in volume of taxable beverages by 51%, and a 29% reduction in sugar intake.

“SA must address commercially driven epidemics with taxes, mandatory food labelling and mandatory comprehensive marketing bans,” Hofman said.

Source: Mail & Guardian

Categories : Diet and Nutrition PaediatricsTags :

Study Reveals More Sugar in Breakfast Products Aimed at Children

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Breakfast products that are aimed at children contain significantly more sugar than those aimed at adults, a Spanish study has revealed.

The researchers analysed a 355 advertisements from 117 different products from 2015 to 2019, and found that the average amount of sugar in the breakfast products analysed and advertised for adults was 10.25%, while for children it was 36.20%.

“Although much of the adult population still adhere to the Mediterranean diet, it is a practice that is waning among children and young people, who are increasingly opting to eat processed industrial products with a high sugar content for breakfast,” explained Mireia Montaña, UOC Faculty of Information and Communication Sciences professor and researcher.

Mònika Jiménez, professor of Advertising and Public Relations at Pompeu Fabra University (UPF) and co-author of another study on breakfast food advertising involving Prof Montaña, warned of persuasive advertising for foods with little nutritional value.

She said, “The less closely a product correlates to that which would be deemed healthy nutritional parameters, the greater the tendency for the advertising discourse to focus on hedonism or happiness and tend towards persuasion.” As Jiménez explained, when such discourse alludes to positive feelings, it stimulates certain areas of the brain that lead us to consume, a strategy which “is especially harmful in relation to certain audiences, such as minors, because they are very susceptible to these kinds of stimuli.”

Profs Montaña and Jiménez found that low nutritional quality breakfast foods were advertised mostly through television (39%), followed by radio (28%), the internet (18%), newspapers (6%), magazines (5%), outdoor advertising (2%) and cinema (0.56%). “TV is the most effective medium when it comes to persuading children. And when is it that children are going to the supermarket with their parents and end up imposing their preferences with regard to what goes into the shopping trolley? Precisely when they are younger, up until preadolescence,” Prof Jiménez pointed out.

Though there are regulations in Spain preventing advertisers from targeting children directly, there are no such restrictions for products which can be aimed at any age group, such as hot chocolate. Advertising aimed at children to use ‘pester power’ on their parents results in food being bought which is then consumed by the entire family. 

Their recommendations included more stringent regulatory frameworks, better nutritional education aimed at parents and children, and added taxes on certain products such as soft drinks.

Source: News-Medical.Net

Journal information: Blasco, M.M., et al. (2021) Breakfast Food Advertisements in Mediterranean Countries: Products’ Sugar Content in the Adverts from 2015 to 2019. Children. doi.org/10.3390/children8010014.

Categories : Diet and Nutrition Skeletal SystemTags :

Plant-based Protein Increases Bone Turnover

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A Finnish study has found that increasing the share of dietary protein from plant versus animal sources leads to increased bone turnover and possible fracture risk.

The 136 adult participants followed one of three diets for a period of three weeks. One of them was modelled on the typical Finnish diet where 70% of protein came from animal sources and the rest from cereals. The second had half the protein come from animal sources and the other half from plants, and the third had 70% of protein from plants and the rest from animal sources

Dairy milk, which is fortified with vitamin D in Finland, was substituted with unfortified plant-based milk, which may have been a confounding variable. There was a marked increase in bone formation and resorption markers, which in the long term could indicate bone loss. These findings are in line with the Oxford-EPIC study, which followed participants for 18 years and found a higher rate of fractures in vegetarians compared to those on an omnivorous diet.

“The results could be different if fluid dairy products had been replaced with plant-based drinks fortified with vitamin D and calcium,” said Docent Suvi Itkonen, Department of Food and Nutrition, Faculty of Agriculture and Forestry, University of Helsinki. “Then again, the average vitamin D intake was also below the recommended level in the group where subjects consumed the animal protein-rich diet, but not to the same extent as in the other groups.”

Source: News-Medical.Net

Journal information: Itkonen, S. T., et al. (2021) Partial Replacement of Animal Proteins with Plant Proteins for 12 Weeks Accelerates Bone Turnover Among Healthy Adults: A Randomized Clinical Trial. The Journal of Nutrition.doi.org/10.1093/jn/nxaa264.

Categories : Cancer Diet and NutritionTags :

Decreasing Cancer Deaths with Population-wide Vitamin D

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Supplementation Scientists have estimated that supplementing the over-50 population in Germany with sufficient vitamin D would save 30 000 lives which would otherwise be lost to cancer, gaining some 300 000 extra years of life, all while reducing healthcare costs.

Vitamin D is created in the body through the interaction of UV-B radiation with dehydrocholesterol, which is produced in the skin, into vitamin D3 (cholecalciferol). In many countries, populations have chronically low vitamin D levels due to more time being spent indoors. Vitamin D supplementation is associated with the prevention and treatment of nutritional rickets and osteomalacia, but it is important for other aspects of health such as prevention of respiratory tract infections and asthma. In countries such as Germany, low sunlight levels for much of the year combined with more time spent indoors results in much of the population having inadequate vitamin D levels. 

Three large meta-analyses had indicated that mortality due to cancer is reduced by 13% with vitamin D supplementation.

“In many countries around the world, the age-adjusted rate of cancer mortality has fortunately declined over the past decade,” said Hermann Brenner, epidemiologist at the German Cancer Research Centre (DKFZ).  However, given the often considerable costs of many new cancer drugs, this success has often come at a high price. Vitamin D, on the other hand, is comparatively inexpensive in the usual daily doses.”

To get their figures, the scientists used a daily administration of 1000 international units of vitamin D, costing 25 Euros per person per year. Since about 36 million people over the age of 50 live in Germany, this results in an annual cost of 900 million Euros.

The researchers calculated the number of years lost to cancer death, and also did not account for testing of vitamin D levels, as the proposed 1000 international units were far short of an overdose danger. The study estimated that if the entire German population over the age 50 were given sufficient supplements to achieve the recommended levels of vitamin D, 30 000 cancers deaths annually would be prevented.

“In view of the potentially significant positive effects on cancer mortality – additionally combined with a possible cost-saving – we should look for new ways to reduce the widespread vitamin D deficiency in the elderly population in Germany. In some countries, foods have even been enriched with vitamin D for many years – for example, in Finland, where cancer mortality rates are about 20 percent lower than in Germany. Not to mention that there is mounting evidence of other positive health effects of adequate vitamin D supply, such as in lung disease mortality rates,” said Brenner, adding, “Finally, we consider vitamin D supplementation so safe that we even recommend it for newborn babies to develop healthy bones.”

Spending about 12 minutes two to three times a week in the sun, with face, hands and parts of the arms and legs all uncovered and without sunscreen is sufficient to provide enough vitamin D.

Source: News-Medical.Net

Journal information: Niedermaier, T., et al. (2021) Vitamin D supplementation to the older adult population in Germany has the cost‐saving potential of preventing almost 30,000 cancer deaths per year. Molecular Oncology. doi.org/10.1002/1878-0261.12924.