Navigating Nutraceuticals: Spermidine | Medical News Bulletin

Wondering what spermidine is and why it’s at the top of the supplement sales stack? Get scientifically sourced, evidence-based information about what it’s for, where it comes from and what it can do for you.

Not interested in where spermidine got its name or what its chemical make-up is? No worries! Just skip to the parts that matters to you.

What is spermidine and why is it called that?

OK, let’s get it out of the way from the start. Why is spermidine called spermidine? Basically, spermidine is a chemical first characterized in sperm in 1926, and when you heat it up with magnesium, it smells like semen. The UK scientists who discovered it named it after its apparent source. Other researchers soon noticed it turning up in rotting tissue along with its close family members: ‘spermine’ and ‘putrescine’.

Would you believe that PhD scientists are every bit as prurient as anybody else? In the course of ginning up on spermidine for this piece, I came across a review article from 1973 that started, ‘Despite the initial aversion to polyamine research which can be attributed to their peculiar nomenclature and to the erroneous idea that polyamines are products of bacterial decay…’

Lucky for us and Philip Larkin, the 1960s heralded a relaxation in social attitudes, and so studying this compound was no longer off the table for ladies and gentlemen of delicate sensibilities.

Spermidine is not, however, only found in sperm.

It’s actually a very important basic chemical contained in every single cell in our body. In fact, it’s in almost every living thing, from plants to bacteria to humans. You could even say it’s one of the fundamental building blocks of life, up there with DNA. So what exatly it? Spermidine is a polyamine. These are small compounds made up of just a few amino groups (one nitrogen atom joined to two hydrogen atoms) linked together by short hydrocarbon chains. Nitrogen, hydrogen and carbon are the main components of amino acids. Short chains of amino acids are called peptides, longer chains are proteins. Our body makes polyamines by using enzymes to break down amino acids.

Why spermidine salespeople claim it’s the cure for all ills

One of the first things you might notice if you’ve tried looking up spermidine in the past is that it seems to be good for everything. Most of these claims are based on research into its biological role, and not grounded in clinical trials. So what is its regular job in our bodies?

Spermidine, spermine and putrescine are very important for our cellular function – if we prevent them from being made by cells, the cells stop growing.

When scientists looked closer, they discovered that spermidine and Co. are an essential component of the machinery our cells use to copy DNA to make RNA, and the machinery we use to build and recycle proteins. Spermidine also has a role in regulating gene expression; it can bind to DNA and chemically change it to switch genes on and off.

In addition to gene function and cellular growth, spermidine helps the synapses in our neurons to fire, stabilizes our cell membranes, assists our immune cells, mediates cell death and is vital for energy production. If you can think of it, spermidine is probably involved in it somehow.

You might hear a lot of talk about spermidine and ‘autophagy’. Autophagy is where cells take old proteins and cellular components, digest them and use the old bits to make new ones, it’s part of the cell’s self-renewal process. Spermidine is important for autophagy because it is a component of the cellular machinery that builds proteins.

Why would I need spermidine?

You probably noticed that I mentioned earlier that we use enzymes to break down amino acids to make spermidine. This means that, unlike nutrients like vitamins, spermidine is not ‘essential’ because we can make it ourselves. The problem is that scientists have discovered that as we age, our capacity to make spermidine from scratch goes down.

As we age, more and more of our cells lose their ability to renew themselves through the process of autophagy. When cells can’t use autophagy to repair and replace aging parts of themselves, they eventually stop doing their jobs, kind of just existing until they die. This is called ‘senescence’.

Scientists looked at old human cultured cells in a senescent state, and compared them with young active cells. The old senescent cells had less than half the amount of spermidine in them, in contrast to young, active cells. Since then, other scientists have found the same thing many times in many different types of cells.

Some scientists think that losing the ability to make spermidine is one of the factors that sends cells into senescence because when they lose spermidine, they lose their regenerative powers. It makes sense, spermidine is a critical component of the machinery our cells use to repair themselves through autophagy and to build the proteins that allow them to do their specialized jobs. If we don’t have spermidine, we can’t transcribe RNA or translate it into proteins.

If we can replace that missing spermidine, the idea goes, then maybe our cells won’t go into senescence so soon, or we might be able to wake them up and get them going again.

Can my body absorb spermidine from supplements?

Yes. Spermidine is water soluble and because it’s so plentiful in our cells and used to build their membranes, it just diffuses right in without any fuss. Whether it changes anything is still up for debate.

Years ago, you might have seen celebrities saying they use anti-aging cream made from horse placenta or salmon sperm. This is because they are both very high in spermidine and formulation chemists thought we might be able to absorb it through our skin.

Can I get it from my regular diet?

Yes. You can get spermidine from food; it’s in everything we eat that still has cells or a lot of protein we can digest into spermidine in it. You might see some articles that say things like ‘spermidine, found in grape fruit’, and others saying, ‘Eat wheat germ for spermidine.’ The truth is, almost every living thing has spermidine in it. The question is not does a food contain it, but more, is a food especially rich in spermidine?

According to food scientists, who have measured the concentrations of spermidine in food, you get the most bang for your buck from offal (that’s internal organs of animals) and processed fish products.

• The best sources of spermidine are:
• Offal (liver/Kidney, etc.)
• Fish
• Legumes (soy beans, adzuki beans, fermented soybeans)
• Fruits like Passionfruit
• Shellfish
• Meat
• Cheese
• Mushrooms
• Wheat germ

You can get spermidine from any protein-rich food.

Does Supplementing Do Anything?

There is laboratory evidence that supplementing with spermidine might help us to live longer and help with cardiovascular health amongst a host of other effects.

A set of animal studies in the late 2010s demonstrated that spermidine helps mice and rats to live longer and lowered their risk of developing hypertension. The researchers discovered that this effect only worked in mice with functioning autophagy systems. This was a big deal because it showed not only that spermidine dietary supplements were useful, they also measured how much spermidine was in the animals as they aged.

Supplements did increase spermidine levels in older animals than ones who didn’t get the supplements. They were also able to narrow down the mechanism by which spermidine was helping the animals to live longer and have healthier arteries. So we have evidence that spermidine is useful and we have a reason to believe it should be, based on its biological function.

What Do the Clinical Trials Say?

There is a huge amount of research focusing on animal trials and cell culture, but at Medical News Bulletin we are all about news you can use, so we’re going to focus on human clinical trials. Specifically, randomized controlled trials, hopefully with a placebo. I didn’t find any relevant meta-analyses or systematic reviews of human clinical trials. This leads me to believe that there have not been many successful trials that met minimum quality standards. This might be a red flag, or it might be a sign that it’s too soon to look.

Looking at the existing research, to be honest, the results are mixed. Some studies show pretty impressive results for spermidine, while others say it does nothing.

Trials That Showed Spermidine Helped

A pilot randomized placebo controlled trial showed spermidine increased COVID vaccine efficacy in older adults with aging immune systems.

German researchers found that increasing daily spermidine through diet slowed progression of cognitive decline in dementia patients. Trial size, 100 patients. Another group found a small reduction in speed of decline in patients with subjective cognitive decline but no dementia diagnosis. Trial size 30 volunteers.

Californian scientists say that the spermidine content in a mixed bag supplement seemed to affect inflammatory markers. This wasn’t especially convincing.

Italian dermatologists claim they showed a topical spermidine lotion reduced hair loss. Trial size, 60 men and women.

Trials that found it didn’t help

A team of nutritionists say that they showed that people who eat more spermidine rich foods have a higher probability of developing colorectal adenomas.

Scientists found that 900 mg spermidine per day for 12 months was no better than a placebo for memory function in older adults. So nearly a gram of the supplement didn’t help prevent Alzheimers or dementia.

Spanish researchers did a huge longitudinal study and saw no link between dietary spermidine and liver function or metabolic health in obese or overweight older adults. Translation, spermidine didn’t prevent liver disease or cardiovascular disease in people with metabolic syndrome.

The jury is out.

Sources

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