What if broad beans could improve decision making in old age?

We’ve all seen it, either in ourselves or others: decision making takes longer as we get older.

But a recent study by Rumana Chowdhury and colleagues suggests that there may be something that some of us can do about it.

Participants were asked to repeatedly select between two images, alternating between the left and right side of a screen. One image consistently gave a reward of 10p, the other did not. The object of the game was to collect as much money as possible, as quickly as possible. A simple enough task, you might believe, but results suggest that older adults were significantly slower and earned less money than their younger counterparts.

Other studies have suggested that dopamine transmission in an area of the brain known as the striatum is very important for decision making. Interestingly, neurons in this area have been shown to die off as we get older and it has been suggested that this is one reason why decision making becomes more difficult as we get older.

But what can we do about this loss of dopamine neurons?

Another well known disease which involves a quicker and more extreme death of dopamine neurons in the same area is Parkinson’s disease. One of the most common treatments for Parkinson’s disease is drugs that contain Levadopa, a synthetic precursor of dopamine, which allows neurons to make more dopamine.

Chowdhury’s group gave the older participants in their study a drug containing Levadopa to see if this would improve their ability to make decisions and found that, indeed, decision making in some subjects was improved.

So does this mean that we should all take Levadopa supplements to help improve our memory as we get older?

Well, the short answer is no. The group actually found that while Levadopa improved decision making in some older people, in others it actually impeded their decision making ability. Further analysis showed that older people who were originally worse at decision making improved after taking levadopa, but those who were originally better in fact got worse.

So it would seem that the connection between dopamine and decision making is by no means straightforward and there is probably an ideal level of dopamine required for successful decision making, but anything more or less than this will impede our ability.

And where do broad beans fit in?

Well, broad beans are a natural source of Levadopa. However, as this study illustrates, getting the dose right is important and we know this is true in the case of Levadopa, as excess Levadopa can result in many, possibly life threatening, side effects. It is therefore vital that you consult your doctor before making any dietary changes.