Diets associated with delaying aging.
brain function and cognitive improvement
The prevalence of insulin resistance, characteristic of type 2 diabetes, increases with age and obesity, increasing the risk of accelerated brain aging, as well as Alzheimer's disease and related dementias, in overweight older adults.
In the study, participants were randomly assigned to either an eight-week intermittent fasting diet or a healthy diet emphasizing fruits, vegetables, whole grains, lean proteins, and low-fat dairy, and restricting added sugars, saturated fats, and sodium.
The intermittent fasting diet consisted of following a healthy diet for five days a week and restricting calories to a quarter of the recommended daily intake for two consecutive days.
Both diets reduced neuronal insulin resistance and had comparable effects on improving insulin signaling biomarkers in neurons, reducing brain glucose, and improving biomarkers of carbohydrate and lipid metabolism.
Both diets improved executive function and memory, with participants who followed the intermittent fasting diet showing greater benefit in strategic planning, switching between two cognitively demanding tasks, recalling cues, and other areas.
Cognitive Health
High blood sugar levels damage cerebral blood vessels and promote deposits on the vessel walls, thus reducing blood flow and nutrient supply to brain cells. This process can cause various limitations, as well as vascular dementia.
Furthermore, glycosaminoglycans, which are complex sugar molecules, can directly impair cognition. They affect the function of synapses between nerve cells and thus affect neuronal plasticity. Experimental data presented at the 2023 American Chemical Society Congress demonstrated this phenomenon.
But twenty years ago, a study provided evidence that a diet high in fat and sugar disrupts neuronal plasticity and may impair hippocampal function in the long term.
Diabetes mellitus can indirectly cause brain damage. Since the 1990s, it has been known that patients with type 2 diabetes have a significantly higher risk of dementia. It is suspected that glucose metabolism is also disrupted in neurons, thus contributing to the development of Alzheimer's disease. Insulin also plays a role in the formation of Alzheimer's plaques.
- Reduce Sugar Consumption
The German Brain Foundation advises minimizing sugar consumption. This process is often challenging; even a small dose of sugar can trigger a signal in the gut, sending signals to the brain via the vagus nerve, thus causing a strong craving for more sugar. "This may be why some people quickly eat an entire chocolate bar after just one piece," said Erbguth. Furthermore, dopamine, a "feel-good hormone," is released in the brain when consuming sugar, leading to a desire for more.
"It is wise to break free from this cycle by largely avoiding sugar," said Dr. Peter Berlit, Secretary-General and spokesperson for the DGN. "The effort is worthwhile, as 40% of all dementia cases and 90% of all strokes are preventable, with many of them linked to industrial sugar," Berlit said.
- Red meat linked to increased risk of dementia
Preliminary research shows that higher intake of processed red meat, including bacon, hot dogs, and ham, is associated with an increased risk of dementia.
Study participants who consumed 0.25 or more servings of processed meat per day (about two servings per week) had a 15% higher risk of dementia compared to those who consumed less than 0.10 servings per day, which equates to about three servings per month.
In addition to an increased risk of dementia, consumption of processed red meat has been associated with accelerated cognitive aging in overall cognition and verbal memory.
However, the study also showed that replacing processed red meat with nuts and legumes could potentially decrease this increased risk. The researchers tested the effects of replacing 1 serving/day of processed red meat with 1 serving/day of nuts and legumes on cognitive outcomes.
They found that replacing legumes and nuts was associated with a 23% lower risk of dementia, less cognitive aging, and a 20% lower chance of subjective cognitive decline.
- Too much coffee is linked to accelerated cognitive decline.
Drinking more than three cups of coffee a day is linked to faster cognitive decline over time, suggest the results of a large study. Researchers examined the impact of different amounts of coffee and tea on fluid intelligence: a measure of cognitive functions including abstract reasoning, pattern recognition, and logical thinking.
Coffee is one of the most consumed beverages worldwide. The beans contain a variety of bioactive compounds, including caffeine, chlorogenic acid, and small amounts of vitamins and minerals.
Consistent evidence from observational and epidemiological studies indicates that coffee and tea consumption has beneficial effects on stroke, heart failure, cancer, diabetes, and Parkinson's disease.
The research group previously published a study with cognitively impaired elderly individuals that found that higher coffee consumption was associated with slower cognitive decline and slower accumulation of cerebral beta-amyloid, present in Alzheimer's disease.
Their current study expands on some of their previous findings and investigates the relationship between coffee and tea intake and cognitive decline over time in a larger sample of older adults.
"We can see that those with high coffee consumption showed the steepest decline in fluid intelligence over the follow-up period, compared to those with moderate coffee consumption and those who never consume coffee," said Sewell, referring to illustrative graphs.
At the same time, "our data suggest that, during this period, moderate coffee consumption may serve as some kind of protective factor against cognitive decline," she added.
For tea, there was a slightly different pattern: people who never drank tea experienced a greater decline in fluid intelligence compared to those who had moderate or high consumption.
Healthy diets promote mental health.
Although randomized clinical trial data are very limited, cross-sectional and longitudinal studies show that healthy diets in young people correlate with mental health: healthier foods reduce internalizing and externalizing disorders, while more typical Western diets increase the risk. On average, dietary interventions include higher levels of fruits and vegetables, fish and nuts, and lower levels of processed foods.
There is no evidence that restrictive diets or fasting are appropriate or safe for young people. Furthermore, involving children in obtaining, growing, or preparing food with gradually increasing autonomy promotes self-confidence and the development of skills.
Nutraceutical options
Foods and plants with specific medicinal or health-promoting properties, also called nutraceuticals or phytopharmaceuticals, have emerging evidence in mental health. A 2022 academic consensus panel of experts reviewed the literature to create clinical guidelines in this area.
For major depression, adding omega-3 fatty acids to standard antidepressant treatment or other treatment improved the condition. St. John's wort has consistent evidence, while probiotics, zinc, turmeric, and curcumin have sufficient, though less robust, evidence.
S-adenosylmethionine, vitamin D, and methylfolate have shown only weak evidence in depression, while vitamin C, magnesium, creatine, N-acetylcysteine, folate, and omega-3s in monotherapy do not have sufficient evidence to be recommended.
For ADHD, there was weak support for vitamin D, but no clear evidence for omega-3s, zinc, Ginkgo biloba, or L-carnitine. For anxiety, there is moderate evidence for ashwagandha and lavender in adults. A review in child psychiatry also suggests trying chamomile for generalized anxiety based on evidence in young adults, and highlights some data for N-acetylcysteine for OCD in particular.
In addition to addressing food security and balanced family meals, specific interventions may be appropriate as adjuncts to initial treatment for mild and some moderate mental illnesses. For more intense moderate to severe illnesses, nutritional psychiatry may be considered in combination with treatments with stronger evidence.
Sources:
https://www.medscape.com/s/viewarticle/995577
https://pubmed.ncbi.nlm.nih.gov/37147037/
https://www.cell.com/cell-metabolism/abstract/S1550-4131(24)00225-0
https://pubmed.ncbi.nlm.nih.gov/38201905/
https://pubmed.ncbi.nlm.nih.gov/32322067/
https://pubmed.ncbi.nlm.nih.gov/26464760/
https://pubmed.ncbi.nlm.nih.gov/12088740/
https://www.acs.org/pressroom/newsreleases/2023/august/sugars-affect-brain-plasticity-helping-with-learning-memory-recovery.html
https://emedicine.medscape.com/article/122501-overview
