Nutrition and its role in maintaining health is incredibly complex, with new connections uncovered every day. This week’s Nutrition news looks at three recently published studies that uncover new links between what we eat and our health, including whether cherries could be the key to our heart health.

Could cherries be the key to heart health?

Nearly 19 million people die every year from heart attacks, strokes, and other cardiovascular diseases (CVD) worldwide. These conditions are primarily caused by atherosclerosis, a stiffening of the arteries often linked to lifestyle choices. A healthy diet, which includes plenty of fresh fruits and vegetables, can help support heart health and reduce the risk of atherosclerosis.

A recent study discussed in the article “Cherries and berries: Nature’s sweet remedy for a healthy heart” pooled data from multiple studies to explore how phenolic compounds in cherries and berries affect cardiovascular health. The study emphasised that atherosclerosis has multiple risk factors, including high cholesterol, inflammation, oxidative stress, smoking, age, hypertension, dyslipidemia, diabetes, and genetic factors. Unhealthy behaviours such as smoking, a sedentary lifestyle, or poor diet significantly contribute to CVD risk.

Cherries and berries, rich in phenolic compounds, are known for their health benefits. These fruits contain flavonoids, stilbenes such as resveratrol, and phenolic acids, which help reduce oxidative stress and inflammation, produce vasodilation, lower blood sugar levels, and offer antimicrobial activity.

Cherries and berries can contain up to 200-300 mg of polyphenols per 100 grams of fresh fruit; a healthy diet rich in fruits and vegetables can provide about a gram of polyphenols per day. These fruits are also abundant in hydroxybenzoic acid and gallic acid, along with flavonoids such as catechin, epicatechin, and quercetin metabolites, and high tannin levels.

This current study found that berry and cherry intake in obese subjects led to blood vessel relaxation and reduced blood pressure, likely due to the fruits' bioactive compounds.

Regular intake of these fruits was shown to lower inflammatory markers and reduce obesity risk, which indirectly lowers CVD risk. The researchers also found that freeze-dried fruit powders maintain their nutritional benefits, making these fruits available year-round.

Regular consumption of cherries and berries enhances antioxidant capacity, reducing cardiometabolic risk, especially in individuals with poor health. Although the optimal daily amount for humans is unclear, up to two cups of these fruits daily is considered safe, aligning with the WHO recommendation of 400 grams of fruits and vegetables per day.

In conclusion, despite variations in fruit types and preparations, this recent study confirms that cherries and berries are beneficial in supporting heart health. Further research is needed to understand these effects fully and translate findings into dietary and public health guidelines to promote fruit intake for heart health management.

Study shows ultra-processed foods lead to cognitive decline

A recent study discussed in the article “Eating more ultra-processed foods tied to cognitive decline, stroke, according to study” suggests that individuals who consume more ultra-processed foods, such as soft drinks, crisps, and cookies, may have a higher risk of memory and thinking problems and stroke than those who consume fewer processed foods. What’s more, the study only shows an association, not a causation.

Ultra-processed foods are typically high in added sugar, fat, and salt, but low in protein and firer. Examples include soft drinks, salty and sugary snacks, ice cream, burgers, canned baked beans, ketchup, mayonnaise, packaged breads, and flavoured cereals. In contrast, unprocessed or minimally processed foods include simple cuts of meats like beef, pork, and chicken, as well as vegetables and fruits.

Dr. W. Taylor Kimberly, MD, PhD, of Massachusetts General Hospital in Boston, stated, "While a healthy diet is important in maintaining brain health among older adults, the most important dietary choices for your brain remain unclear. We found that increased consumption of ultra-processed foods was associated with a higher risk of both stroke and cognitive impairment, and the association between ultra-processed foods and stroke was greater among Black participants."

The study followed 30,239 individuals aged 45 or older who identified as Black or white, over an average of eleven years. Participants filled out questionnaires detailing their diet, and researchers calculated the proportion of ultra-processed foods consumed daily. Participants were divided into four groups based on their intake of processed foods.

Of the participants, 14,175 were assessed for cognitive decline, and 20,243 for stroke, with no prior history of these conditions. By the end of the study, 768 people had developed cognitive impairment, and 1,108 had experienced a stroke.

For those with cognitive issues, those affected consumed 25.8% of their diet in ultra-processed foods, compared to 24.6% for those without cognitive problems. A 10% increase in ultra-processed food consumption was linked to a 16% higher risk of cognitive impairment, while consuming more unprocessed or minimally processed foods was associated with a 12% lower risk.

In the stroke group, those who had a stroke consumed 25.4% of their diet in ultra-processed foods, compared to 25.1% for those who did not. Higher intake of ultra-processed foods was associated with an 8% increased risk of stroke, while more unprocessed food intake was linked to a 9% reduced risk. The risk was particularly higher among Black participants, with a 15% increase in stroke risk.

Dr. Kimberly concluded, "Our findings show that the degree of food processing plays an important role in overall brain health. More research is needed to confirm these results and to better understand which food or processing components contribute most to these effects."

The study's limitation is that it only included participants who identified as Black or white, so results may not be applicable to other populations and further research is needed.

Vitamin D deficiency linked to diabetes risk

A recent systematic review and meta-analysis, discussed in the article “Low vitamin D levels linked to higher diabetes risk in older adults, study finds”, investigated whether low serum vitamin D (25-hydroxyvitamin D or 25OHD) levels could predict the onset of type 2 diabetes (T2D) in older adults. The study found that even after adjusting for several confounders, low 25OHD levels were linked to an increased risk of developing T2D in this demographic.

According to the International Diabetes Federation (IDF), the global prevalence of diabetes among individuals aged 20-79 was 536.6 million in 2021, with projections suggesting the number of people needing some form of diabetes support will rise to 783.2 million by 2045. Older adults, particularly those aged 75-79, show the highest prevalence of diabetes, significantly impacting health care expenditures.

Vitamin D deficiency, common among older adults, is associated with an increased risk of T2D due to its roles in insulin secretion, metabolic syndrome management, inflammation control, and genetic factors. Although observational studies and meta-analyses suggest an inverse relationship between 25OHD levels and diabetes risk, intervention studies provide mixed results. Thus, this study aimed to clarify the link between low serum 25OHD levels and T2D onset in older adults.

The study included longitudinal, prospective studies from PubMed and SCOPUS databases, focusing on self-reported diabetes diagnoses, medical records, or American Diabetes Association criteria. The updated review encompassed 12 studies with 40,664 older adults from European and North American populations, with a mean age of 69.1 years and 66% female participants. The median follow-up period was 7.3 years.

Data extracted included demographics, sample sizes, follow-up durations, serum 25OHD levels, diabetes diagnostic criteria, and covariates. A random effects meta-analysis calculated pooled relative risks (RRs), and secondary analyses adjusted for covariates. The study found that lower baseline 25OHD levels were significantly associated with a higher risk of developing diabetes in older adults, even after adjusting for confounders (hazard ratio = 1.22).

The results indicate that vitamin D influences T2D risk through mechanisms such as insulin secretion modulation, insulin resistance reduction, and inflammation attenuation. The study's robust methodology, including a large sample size and extensive covariate adjustments, underscores the significance of maintaining adequate vitamin D levels for metabolic health in older adults.

In conclusion, the meta-analysis confirms that low vitamin D levels are associated with an increased risk of T2D in older adults, even after accounting for various confounders. This emphasises the importance of vitamin D beyond bone health and highlights the need for further research, particularly in very old populations.

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Alison Astill-Smith author Alison is the Founder of Metabolics who writes about Metabolics updates, events and natural healthcare. Her experience and passion for natural supplements and healthcare comes from her years of experience as a practising osteopath, having founded Metabolics in her search for high quality, natural products in her own work. Alison has been a qualified and practising Osteopath since 1981 and regularly gives seminars on a range of healthcare subjects to the wider practitioner community helping share her knowledge and experience.