- Two spices have been implicated in fighting Alzheimer's (and thus age-related cognitive decline): turmeric and cinnamon.
- Two herbs have been implicated in fighting Alzheimer's as well as being linked to better cognitive performance: sage and lemon balm.
- Another two herbs have also been linked to better cognitive performance: rosemary and peppermint.
- For those who suffer from sleep or stress problems (both of which contribute to cognitive problems), there is some evidence that, in keeping with traditional beliefs, chamomile and lavender both have calming effects.
There hasn't been a lot of research into the effects of herbs and spices on cognition and the brain, unfortunately. But on the positive side, the risk of side-effects is very low, so we don't need a lot of evidence for it to be worth trying.
Spices
Probably the most researched of these substances is the curry spice turmeric, more specifically one of its components, called curcumin. This has been found to be a powerful antioxidant and anti-inflammatory, which affects the brain protein BDNF (involved in the creation of new neurons). Research also suggests it may be protective against amyloid plaques, and so help fight Alzheimer's.
These findings have had an effect on my own cooking — I habitually cook up a lot of vegetables in the wok for our evening meal, and I add turmeric to the mix (heating it, along with some other curry spices, in the oil before adding the veges), so I have turmeric most days. Cumin, by the way, is (notwithstanding the similarity in names) something completely different.
Another spice that may be helpful, and one that is even easier to add to your daily diet, is cinnamon. I’ve been happily generous with cinnamon on my breakfast ever since the first hints came out that cinnamon might help protect against Alzheimer’s (it’s not like it’s an ordeal to add cinnamon!). Now we have more evidence, with a finding that two compounds found in cinnamon —cinnamaldehyde and epicatechin — appear to help prevent tau tangles (one of the characteristics of Alzheimer’s).
Herbs
As for herbs, there's a researcher in Britain who takes an interest in herbs, and it's really solely down to him and his students that we have any idea about the effects of herbs on cognition. Because they're all from one lab, and because the studies are invariably quite small, and the issue difficult to study, we can't put too much weight on these findings. But, as I say, where's the harm?
Four herbs have been put forward as helpful for the brain. Sage and lemon balm seem to increase the activity of acetylcholine, and so may be helpful to protect against Alzheimer's. They have also been linked to better cognitive performance. The scent of rosemary (i.e. from essential oil) has also been linked to better cognition, as has drinking peppermint tea.
From a more indirect perspective, chamomile tea and the scent of lavender have both been linked to feelings of calmness, which might help those who suffer from sleep problems. Lemon balm has also been linked to greater feelings of calmness.