Processed Meats Increase Risk of Dementia

A recent study published in Neurology on 11 February 2025, led by researchers from Brigham and Women’s Hospital, has investigated the relationship between long-term red meat consumption and the risk of dementia and cognitive decline in U.S. adults. The study utilised data from the Nurses’ Health Study and the Health Professionals Follow-Up Study, encompassing approximately 170,000 participants over a 43-year period. 

Key Findings:

• Processed Red Meat and Dementia Risk: Individuals with the highest intake of processed red meats—such as bacon, sausages, and hot dogs—exhibited a 13% higher risk of developing dementia compared to those with lower consumption levels.
• Cognitive Decline: High consumption of processed red meats was associated with a 14% increase in subjective cognitive decline, indicating a perceived worsening of cognitive abilities over time.
• Unprocessed Red Meat: The study found that unprocessed red meats, such as beef, lamb, and pork, also contributed to cognitive risks, potentially due to harmful substances like nitrates, sodium, and saturated fats present in these meats.

Mechanisms Behind the Findings:

The detrimental effects of processed red meats on cognitive health are believed to be linked to several factors:

• Nitrates and Nitrites: Commonly used as preservatives in processed meats, these compounds can form nitrosamines, which have been implicated in neurodegenerative processes.
• High Sodium Content: Elevated sodium levels can lead to hypertension, a known risk factor for vascular dementia.
• Saturated Fats: High levels of saturated fats in processed meats are associated with cardiovascular diseases, which can indirectly affect brain health.

Dietary Recommendations:

Based on the findings, the researchers suggest several dietary modifications to mitigate dementia risk:

• Reduce Processed Red Meat Intake: Limiting the consumption of processed meats can lower the risk of cognitive decline.
• Substitute with Healthier Protein Sources: Replacing processed red meats with alternatives such as fish, poultry, nuts, and legumes has been associated with a reduced risk of dementia. For instance, substituting processed red meat with fish was linked to a 28% reduction in dementia risk.
• Adopt Brain-Healthy Diets: Diets like the Mediterranean, DASH, and MIND diets, which are low in red meat and rich in fruits, vegetables, whole grains, and healthy fats, have been associated with decreased dementia risks.

Conclusion:

This extensive study underscores the importance of dietary choices in maintaining cognitive health. Limiting the intake of processed red meats and opting for healthier protein sources may significantly reduce the risk of dementia and support long-term cognitive function.

Food Choices Affect Pain

Introduction

Chronic pain is a widespread issue that significantly impacts quality of life and healthcare systems. While obesity is a well-documented risk factor for chronic pain, recent evidence suggests that other factors, such as diet quality, may also play a role. A recent study explores the relationship between diet quality and body pain in adults, regardless of their levels of adiposity (body fat).

Objective

The primary aim was to investigate whether better diet quality is linked to lower levels of body pain in adults and whether this association remains significant independent of adiposity.

Methods

The research used data from the Whyalla Intergenerational Study of Health, which includes a diverse sample of adults from Whyalla, South Australia. Participants completed detailed assessments, including:

• Diet quality evaluation: Using the Australian Recommended Food Score (ARFS), which measures adherence to dietary guidelines.
• Body pain measurement: Using validated self-reported questionnaires that assess the severity and frequency of pain across the body.
• Adiposity indicators: These included body mass index (BMI), waist circumference, and body fat percentage.
  The study also controlled for confounding factors such as age, sex, physical activity, smoking status, and socio-economic status.

Key Findings

1. Diet Quality and Pain:
   • Higher ARFS scores, indicating better diet quality, were significantly associated with reduced levels of body pain.
   • The association was consistent across various demographic and lifestyle groups.
2. Independence from Adiposity:
   • While higher adiposity was associated with increased body pain, the relationship between diet quality and pain remained significant even after adjusting for adiposity measures.
   • This suggests that diet quality has an independent role in pain modulation.
3. Potential Mechanisms:
   • Nutritional components such as anti-inflammatory foods, antioxidants, and omega-3 fatty acids might contribute to reduced systemic inflammation and pain perception.
   • Conversely, poor diet quality may exacerbate pain through increased inflammation and metabolic dysregulation.

Implications

The findings highlight the importance of a high-quality diet in managing body pain, regardless of body fat levels. This has potential implications for public health strategies and clinical interventions aimed at reducing chronic pain prevalence.

• For individuals: Encouraging adherence to dietary guidelines may help alleviate body pain alongside other health benefits.
• For policymakers and healthcare providers: Integrating dietary advice into pain management protocols could improve patient outcomes.

Conclusion

The study concludes that better diet quality is associated with reduced body pain in adults, and this relationship is independent of adiposity. These results underscore the importance of dietary quality as a modifiable factor in chronic pain prevention and management. Further research is needed to explore specific dietary components and their mechanisms in influencing pain pathways.

This research supports the broader understanding that nutrition plays a critical role in overall health and highlights diet quality as a key factor in pain management strategies.

Sweeteners Increase Cardiovascular Risk

Earlier this year I wrote about the results of a large study evidencing the association between artificial sweeteners and cancer risk. Debras et al. used the same cohort (Nutrient-Sante) of over 100,000 participants. But this time, they looked at the association between artificial sweeteners and cardiovascular disease risk. The study was published in The British Medical Journal last month.

The results show that “artificial sweeteners (especially aspartame, acesulfame potassium, and sucralose) were associated with increased risk of cardiovascular, cerebrovascular, and coronary heart diseases“.

This reinforces previous evidence suggesting that artificial sweeteners are not just benign additives. They may actually have a detrimental impact on health.

Vitamin D and Alzheimer’s Disease

Unfortunately there is currently an absence of curative and preventative interventions for Alzheimer’s Disease (AD). Last year, Panza et al. reviewed the research on the links between vitamin D and AD. Low vitamin D levels have been associated with an accelerated decline in cognitive functions. They have also been associated with the development of chronic brain conditions such as AD and other dementias. As such, vitamin D is often thought of as a neurosteroid due to its effect on brain conditions. The authors believe more research is required to determine the effect of vitamin D supplementation on the prevention and/or treatment of AD.

Eating For Health And Longevity

Valter Longo et al. recently published a paper that examined research on the relationships between nutrition, health and longevity. Here are some of the main components of a longevity diet:

• mid to high carbohydrate intake (45-60%) – mostly non-refined
• fat intake (25-35%) – mostly plant-based
• low protein intake (10-15%) – mostly plant-based but includes regular consumption of peso-vegetarian-derived proteins. Low protein intake or normal protein intake (with high legume consumption) lowers the intake of amino acids such as methionine. This in turn lowers pro-aging substances such as GHR, IGF-1, insulin and TOR-S6K.
• over 65s need to be careful to avoid malnourishment and prevent frailty and diseases resulting from reduced muscle mass, reduced bone mass or low blood cell count.
• the largest gains in longevity come from diets rich in legumes, whole grains and nuts. With reduced amounts of red meat and processed meats
• a 12-13hr daily fasting period is key to reducing the insulin resistance that may have developed from a high calorie diet. The fasting window also helps decrease levels of IGF-1, lowers blood pressure, lowers total cholesterol and decreases inflammation.
• our daily food intake should be established by our body fat/lean body mass composition rather than generic pre-set calorie amounts.

Nutrition, Immunity and COVID-19

Our immune system protects us from pathogens like viruses, bacteria, cancerous cells, etc. and it can be separated into 2 distinct branches: the innate immune system and the adaptive immune system. Our innate immune system uses cells such as macrophages, neutrophils and mast cells to mount a fast, generic response to pathogens. Inflammation is the hallmark of the innate immune system. On the other hand, the adaptive immune system uses T cells, B cells and natural killer cells to mount a slow, targeted response to pathogens. It’s the adaptive immune system that’s responsible for life-long immunity to certain diseases. In practice, the 2 branches interact to provide a comprehensive immune response.

In a recent article, Butler and Barrientos (2020) summarised the interactions between diet, immunity and COVID-19. They state that the typical western diet (high in saturated fats, refined carbohydrates and sugars, and low in fibre, unsaturated fats and antioxidants) “significantly impairs adaptive immunity while ramping up innate immunity, leading to chronic inflammation and severely impairing host defence against viral pathogens.”

The authors note that “T and B cell counts were also significantly lower in patients with severe COVID-19; thus, there could be a potential interaction between western diet consumption and COVID-19 on adaptive immunity impairment.” They suggest the higher rates of obesity and diabetes among ethnic minority populations may partly account for the health disparities seen in response to COVID-19.

Butler and Barrientos conclude “that individuals refrain from eating foods high in saturated fats and sugar and instead consume high amounts of fibre, whole grains, unsaturated fats, and antioxidants to boost immune function.”

Early Feeding Improves Pre-Diabetes and Blood Pressure

About a year ago Sutton et al. published a study that showed that intermittent fasting has benefits that are independent of food intake and weight loss. Their trial tested the effects of 5 weeks of “early time-restricted feeding” (eTRF) on 8 men with pre-diabetes. The subjects were asked to start breakfast between 6:30-8:30 and to eat their 3 meals in a 6-hour window with dinner before 15:00. They were fed enough food to maintain weight. The control group had similar meals but within a 12-hour feeding window. Five weeks of eTRF significantly improved insulin levels, insulin sensitivity, blood pressure and oxidative stress levels. The blood pressure improvements were particularly dramatic – morning levels of both systolic and diastolic blood pressure were reduced by about 10 mm Hg each.

Some of the benefits of eTRF are believed to originate from eating in alignment with our internal biological clocks which are primed for feeding early in the day. The authors state that “in humans, insulin sensitivity, beta cell responsiveness, and the thermic effect of food are all higher in the morning than in the afternoon or evening, suggesting that human metabolism is optimized for food intake in the morning”. Fortunately eTRF lowers the desire to eat in the evening!

Meal Times Crucial For Weight Loss

A few months ago Lopez-Minguez et al. reviewed studies looking at the effect of meal times on obesity and metabolic risk. Their findings are summed up in the following points:

• skipping breakfast is linked to obesity
• eating a large breakfast (within 2hrs of waking) decreases the probability of being obese by 50%
• a late lunch (after 3pm) hampers weight loss and has a negative effect on the diversity and composition of our microbiota
• a late dinner (less than 2hrs before bedtime) decreases glucose tolerance
• eating a large, late dinner (less than 2hrs before bedtime) leads to a 5-fold increase in the risk of becoming obese
• the timing of breakfast seems to be hereditary whereas the timing of dinner is mainly cultural

There may be some truth in the following quote by Adelle Davis.

“Eat breakfast like a king, lunch like a prince and dinner like a pauper”

As well as getting the timing right obviously!

Excess Dietary Salt Leads To Cognitive Impairment

Faraco et al. recently discovered mechanisms by which salt-rich diets can lead to cognitive dysfunction in mice. An increase in dietary salt led to a deficiency of nitric oxide in cerebral blood vessels. As nitric oxide is a vasodilator, the reduced levels resulted in decreased cerebral blood flow. In addition, nitric oxide deficiency causes the distortion of a brain protein (tau) which affects the structure and function of nerve cells. The authors conclude that the “avoidance of excessive salt intake and maintenance of vascular health may help stave off the vascular and neurodegenerative pathologies that underlie dementia in the elderly.”

Paleo Diet May Be Bad For Cardiovascular Health

Research published earlier this month in the European Journal of Nutrition questions the health benefits of the Paleolithic diet. The Paleo diet claims to mimic the diet of our ancestors. It’s high in meat, fruits, vegetables, nuts and seeds but avoids dairy, legumes and grains.

Genoni et al. studied a group of about 100 people over a year. Half the group followed a Paleo diet and the rest followed a diet typical of national recommendations. The authors found that there was a significant difference in the gut bacteria between groups, with an increased presence of Hungatella in the paleo group. Hungatella produces trimethylamine-N-oxide (TMAO), a gut-derived metabolite associated with cardiovascular disease. Consequently the levels of TMAO were higher in the Paleo group and this was inversely associated with whole grain intake.

The authors conclude that “although the Paleo diet is promoted for improved gut health, results indicate long-term adherence is associated with different gut microbiota and increased TMAO. A variety of fiber components, including whole grain sources may be required to maintain gut and cardiovascular health.”