Chapter 9
Spermidine
And soy milk? In a test tube, phytonutrients in coffee bind not only to proteins from milk, but also from eggs and soy. Eggs have not yet been tested in humans, so the experts still don’t agree on whether an omelet with black coffee would hinder absorption, but for soy there seems to be an all-clear. Soy proteins do initially bind the coffee components in the small intestine, but our good bacteria release them again, so that they can be absorbed farther down in the gut. Other non-animal milks, such as almond, rice, oat, and coconut milk, contain so little protein that I would assume there is no binding problem, but they still need to be tested directly.
Freeze-drying and spray-drying, which is how instant coffee is made, does not appear to materially affect the amount of chlorogenic acid, unlike the preparation method for fresh coffee. Filter coffee has a higher chlorogenic acid content than espresso, presumably because the water and ground coffee are in contact longer, and also because the drink is ultimately larger.
The preparation method also determines coffee’s effect on our cholesterol. See see.nf/cafestol for why brewing with paper filters is preferable. A study from Norway that followed a half-million men and women for an average of 20 years seemed to confirm the cholesterol question for the general population. Those who filtered with paper had an even lower mortality rate than those who drank unfiltered coffee. In response to these results, some began to lament the growing popularity of “unfiltered” coffee from capsule machines, but those small plastic cups actually contain a paper filter. Capsule coffee does, however, contain more estrogen-like chemicals, like any heated plastic (whether BPA-free or not), but the amounts found were low relative to current safety guidelines.
Reason for concern?
Coffee is not for everyone. People with glaucoma, or those with a family history of it, should stay away from caffeinated coffee. Its consumption is also associated with bladder weakness in women and men. In individual cases of epilepsy, there were fewer seizures after patients stopped drinking coffee; therefore it is certainly worth a try to avoid coffee if one is prone to seizures. Coffee may also worsen reflux disease. Finally, it almost goes without saying that you shouldn’t consume as much caffeine if you suffer from insomnia. Just a single cup of caffeinated coffee in the evening can lead to a considerable deterioration in sleep quality.
There is also a consistent association between coffee consumption and pregnancy complications, including miscarriages, preterm births, and low birth weight. Coffee consumption has not been linked to birth defects, but it may increase the risk of childhood leukemia.
And don’t administer it from the wrong end. A recent review on the dubious safety of coffee enemas warned against them and pointed to reports of colitis, electrolyte imbalance, rectal burning, and intestinal perforation.
Don’t forget that daily consumption of caffeinated beverages can lead to physical dependence. It’s no coincidence that Americans alone spend almost 75 billion dollars a year on the stuff. Caffeine withdrawal can cause headaches lasting days, fatigue, concentration problems, and mood swings. Ironically, coffee addiction might be a good thing. If it is indeed confirmed that coffee induces autophagy and prolongs life, then the daily habit would ultimately be useful.
Spermidine
In 1676, Antoine van Leeuwenhoek, the father of microscopy, was the first person ever to see bacteria. The following year he examined his own semen, and another year later, in 1678, he discovered that tiny crystals had formed in the seminal fluid he had not wiped away. Centuries later, this substance was named spermine. Both it and its precursor spermidine are found throughout the body, so their names are pure coincidence. In 1885, spermine was independently discovered in brain tissue and called “neuridine,” but when it turned out to be the same substance as spermidine, the original drastic designation stuck.
Spermidine plays a key role in regulating cell growth. It is positively charged, so it naturally binds to negatively charged molecules like DNA. Spermidine fits precisely into the major and minor grooves of the DNA helix. Most of the spermidine in our body is actively bound to genetic material, stabilizing the genetic code so it is transmitted correctly. In addition, spermidine is a potent activator of autophagy.
The spermidine in our tissues comes from three sources. Cells can produce it themselves from an amino acid called arginine. Some gut bacteria are also capable of doing so, or we can take it in already formed through the diet. Certain foods naturally contain plenty of it. Once ingested, spermidine is quickly absorbed and circulates throughout the body to contribute to cellular pools. When mice are fed extra spermidine, they live up to 25 percent longer and are healthier. Similar benefits for lifespan and health span have also been found in other tested species, as detailed in the groundbreaking article “Induction of autophagy by spermidine promotes longevity.”
The problem is that spermidine levels decline with age. By 50, we have only half as much of it. This drop is observed across the entire biological spectrum, but there is a remarkable exception.
The naked mole rat lives an astonishing 10- to 20-times longer than other similarly sized rodents, and it does so without any visible signs of aging. The animals can live for decades without showing typical signs of deterioration such as loss of fertility or muscle mass. The naked mole rat is considered a “non-aging mammal.” This astonishing feat could have to do with maintaining consistently high spermidine levels throughout its entire life, because the same was also found in 100-year-old humans.
Italian researchers found that in most people over 60 or 70, spermidine levels had already fallen to about one third of what had been measured in their middle years. Yet those over 90 were somehow able to maintain their youthful spermidine levels, presumably because their bodies produced more of it. But we might also replenish the declining level from the outside through a spermidine-rich diet. Soybeans and mushrooms have been suggested, but as we will learn, wheat germ is an even more concentrated natural source.
What is especially encouraging about the rodent studies is that the additional spermidine from food extended lifespan even when it was administered to old mice; translated to humans, that would mean changing one’s diet when one is already over 50. Significant anti-aging effects were also found in all vital organs—the heart, kidneys, and liver—and in increased autophagy in the brain.
Wheat Germ Against Dementia
In see.nf/wheatgerm I go through all the trials with spermidine related to cognitive performance, including a remarkable study in which randomly selected participants who ate rolls baked with added wheat germ (instead of wheat bran) experienced cognitive improvements “that went far beyond any treatments against dementia available to date.”
Not Pulled Out of Thin Air
Our hair roots, one of the most active tissues in all of mammalian biology, are true little spermidine machines. In see.nf/spermidinehair I show that the daily intake of spermidine, equivalent to half a teaspoon of wheat germ, substantially reduced hair loss (determined by the pull test, in which hair is actually pulled), even months after the end of the study.
Are Antibodies Out?
For long-term immunity, we need to maintain our antibody-producing cells with Methuselah-like qualities, but the amount of spermidine in cells declines with age, autophagy decreases, and so does the functionality of immune cells. As I show in see.nf/immuneheart, restoring youthful spermidine levels can improve antibody production in immune cells taken from older adults, indicating that spermidine helps “reverse immune aging.”