Here's a May 14, 2021 article about animal and human studies of a food-related nutrient with the memorable name of "spermidine" that may protect mitochondria in aging brains and reduce amyloid and tau. Better Living Through Polyamines? (Yes, it's in sperm, but also in cheddar cheese, broccoli, wheat germ and Japanese natto) A study of northern Italians eating a Mediterranean diet seemed to do better if they reported higher daily intake of foods high in spermidine:
And as a bonus, here's a comment provided by ALZFORUM from an Italian researcher that may be of interest to those concerned about either dairy or cholesterol:[P]eople who ate foods high in spermidine were also less susceptible to cognitive decline. For example, the estimated dietary spermidine content correlated with higher scores on the mini-mental state exam at baseline and with less slippage on this brief memory screen over time. People who had more dietary spermidine were less likely to become cognitively impaired during the five-year follow-up. Participants also took a cognitive test battery developed by the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD). There, too, spermidine intake was tied to scores in domains of memory, executive function, and cumulative impairment.
The authors acknowledged the possibility that other components in the diet could have contributed to the effects. However, when they controlled for diet quality using the Alternate Healthy Eating Index, [estimated]spermidine levels still correlated with better cognition. The Bruneck study did not measure spermidine levels directly...
[In a German study of a cohort of 160 participants aged 60–90, including 108 with subjective cognitive complaints, these researchers found that dietary spermidine intake was tied to hippocampal volume and cortical thickness. Adherence to a Mediterranean diet also correlated with these structural features of brain health, and the researchers reported that spermidine intake substantially contributed to this association....a few slices of aged cheddar cheese (10 g) or an extra helping of broccoli (60 g) each contain about 2 mg spermidine (Atiya Ali et al., 2011). Though dietary sources of polyamines differ markedly by region, many choices exist, as polyamine-rich foods include soybeans, mushrooms, green peas, eggplant, and citrus fruits.
Or as my husband helpfully suggested: "If you're aging, your cheese should be also!" Time for a recipe with aged cheddar on broccoli with mushrooms and eggplant!Of note, spermidine is present in many foods, some of which are peculiar to the Mediterranean diet, which is known to lower risk of dementia. There are many other foods, such as seasoned cheese, that contain high levels of spermidine and that are omitted from the diets of aging people in the attempt to control cholesterol; the cost/benefit analysis of these nutritional choices should take into account the protective role of polyamine in aging and neurodegenerative disorders.