It’s Q&A Day at 10almonds!

Have a question or a request? We love to hear from you!

In cases where we’ve already covered something, we might link to what we wrote before, but will always be happy to revisit any of our topics again in the future too—there’s always more to say!

As ever: if the question/request can be answered briefly, we’ll do it here in our Q&A Thursday edition. If not, we’ll make a main feature of it shortly afterwards!

So, no question/request too big or small 😎

❝How much evidence is there behind the longevity-related benefit related to spermidine, and more specifically, does it cause autophagy?❞

A short and simple answer to the latter question: yes, it does:

Spermidine: a physiological autophagy inducer acting as an anti-aging vitamin in humans?

For anyone wondering what autophagy is: it’s when old cells are broken down and consumed by the body to make new ones. Doing this earlier rather than later means that the genetic material is not yet so degraded when it is copied, and so the resultant new cell(s) will be “younger” than if the previous cell(s) had been broken down and recycled when older.

Indeed, we have written previously about senolytic supplements such as fisetin, which specialize in killing senescent (aging) cells earlier:

Fisetin: The Anti-Aging Assassin

As for spermidine and longevity, because of its autophagy-inducing properties, it’s considered a caloric restriction mimetic, that is to say, it has the same effect on a cellular level as caloric restriction. And yes, while it’s not an approach we regularly recommend here (usually preferring intermittent fasting as a CR-mimetic), caloric restriction is a way to fight aging:

Is Cutting Calories The Key To Healthy Long Life?

As for how spermidine achieves similarly:

Spermidine delays aging in humans

However! Both of the scientific papers on spermidine use in humans that we’ve cited so far today have conflict of interests statements made with regard to the funding of the studies, which means there could be some publication bias.

To that end, let’s look at a less glamorous study (e.g. no “in humans” in the title because, like most longevity studies, it’s with non-human animals with naturally short lifespans such as mice and rats), like this one that finds it to be both cardioprotective and neuroprotective and having many anti-aging benefits mediated by inducing autophagy:

A review on polyamines as promising next-generation neuroprotective and anti-aging therapy

(the polyamines in question are spermidine and putrescine, which latter is a similar polyamine)

Lastly, let’s answer a few likely related questions, so that you don’t have to Google them:

Does spermidine come from sperm?

Amongst other places (including some foods, which we’ll come to in a moment), yes, spermidine is normally found in semen (in fact, it’s partly responsible for the normal smell, though other factors influence the overall scent, such as diet, hormones, and other lifestyle factors such as smoking, alcohol use etc) and that is how/where it was first identified.

Does that mean that consuming semen is good for longevity?

Aside from the health benefits of a healthy sex life… No, not really. Semen does contain spermidine (as discussed) as well as some important minerals, but you’d need to consume approximately 1 cup of semen to get the equivalent spermidine you’d get from 1 tbsp of edamame (young soy) beans.

Unless your lifestyle is rather more exciting than this writer’s, it’s a lot easier to get 1 tbsp of edamame beans than 1 cup of semen.

Here are how some top foods stack up, by the way—we admittedly cherry-picked from the near top of the list, but wheatgerm is an even better source, with cheddar cheese and mushrooms (it was shiitake in the study) coming after soy:

Frontiers in Nutrition | Polyamines in Food

Alternatively, if you prefer to just take it in supplement form, here’s an example product on Amazon, giving 5mg per capsule (which is almost as much as the 1 cup of semen or 1 tbsp of edamame that we mentioned earlier).

Enjoy!

It’s Q&A Day at 10almonds!

Have a question or a request? We love to hear from you!

In cases where we’ve already covered something, we might link to what we wrote before, but will always be happy to revisit any of our topics again in the future too—there’s always more to say!

As ever: if the question/request can be answered briefly, we’ll do it here in our Q&A Thursday edition. If not, we’ll make a main feature of it shortly afterwards!

So, no question/request too big or small

❝What effect does refrigeration have on the nutritional value of fruit and vegetables??❞

It’s difficult to give a single definitive answer, because naturally there are a lot of different fruits and vegetables, and a lot of different climates. The answer may be different for tomatoes in Alaska vs bananas in Arizona!

However, we can still generalize at least somewhat

Refrigeration will generally slow down any degradation process, and in the case of fruit and vegetables, that can mean slowing down their “ripening” too, as applicable.

However…

Refrigeration will also impede helpful bioactivity too, and that includes quite a list of things.

Here’s a good study that’s quite illustrative; we’d summarize the conclusions but the rather long title already does that nicely:

Storage of Fruits and Vegetables in Refrigerator Increases their Phenolic Acids but Decreases the Total Phenolics, Anthocyanins and Vitamin C with Subsequent Loss of their Antioxidant Capacity

So, this really is a case of “there are pros and cons, but probably more cons on balance”.

In practical terms, a good take-away from this can be twofold:

1. don’t keep fruit and veg in the fridge unless the ambient temperature really requires it
2. if the ambient temperature does require it, it’s best to get the produce in fresh each day if that’s feasible, to minimize time spent in the fridge

An extra thing not included there: often when it comes to the spoilage of fruit and veg, the problem is that it respires and oxidizes; reducing the temperature does lower the rate of those, but often a far better way is to remove the oxygen. So for example, if you get carried away and chop too many carrot batons for your hummus night, then putting them in a sealed container can go a long way to keeping them fresh.

See also: How Does the Nutritional Value of Fruits and Vegetables Change Over Time?

Enjoy!