Recently, experts from the Chinese Academy of Sciences have revealed the mechanism of action of nicotine to improve metabolism and delay aging through experiments, providing a new technical direction for the expansion of nicotine application and anti-aging.
On the other hand, the research team of the University of Braga Minho in Portugal, using chick embryo experiments, proved that e-cigarette aerosols have little harm to lung and embryonic development, much lower than traditional cigarette smoke. This experiment and the results of the study fully provide information on the impact of e-cigarettes on embryonic development, and the researchers recommend that relevant tobacco control for pregnant women addicted to nicotine can provide e-cigarettes as a safer nicotine alternative.
How can these experiments be interpreted scientifically? How might it be applied in the future?
Looking at this study, many people may be thinking:
Since nicotine can be anti-aging, is it possible to smoke cigarettes and electronic cigarettes casually?
Stop being delusional.
The nicotine anti-aging pathway discovered by the Chinese Academy of Sciences team is actually the NAD pathway that has been very popular in the anti-aging circle.
Let's start with what this NAD is.
NAD, Chinese known as nicotinamide adenine dinucleotide, a coenzyme of many dehydrogenases in the human body, referred to as coenzyme I., plays a vital role in the tricarboxylic acid cycle (the final metabolic pathway of the three major nutrients) and the respiratory chain (the basic function of mitochondria).
respiratory chain
The reason why NAD is so important is that the biochemical reactions in the human body are basically redox reactions, and the main redox pathways related to respiration and metabolism are achieved by losing hydrogen and obtaining hydrogen. NAD is one of the key intermediates.
It exists in two forms: NAD+ and NADH.
Oxidized NAD+ can take away hydrogen, and reduced NADH can provide hydrogen.
NAD+ and NADH conversion (red box)
The authority of NAD research is unquestionable. In total, more than a dozen Nobel Prizes have been produced in this field.
The early three bigwigs:
Such an important pair of characters in the human body is born to play two different functions: offensive and defensive.
To put it bluntly, the level of NAD in the human body actually represents the level of metabolic capacity, and as the human body ages, NAD levels will naturally decline. Anti-aging by boosting NAD levels is naturally an excellent way to do so. Later studies have indeed proved the association between NAD+ and aging and anti-aging [1].
There are two main ways for NAD+ to come from in the human body:
De novo synthesis pathway (kynurate pathway + Preiss-Handler pathway), remedial pathway
It can be seen that there are five main precursors for the synthesis of NAD+:
NA (niacin), Trp (tryptophan), NAM (niacinamide), NR (nicotinamide ribose), NMN (nicotinamide mononucleotide)
The conversion process from NAM to NMN is catalyzed by NAMPT.
Therefore, these supplements have also become a big hit for anti-aging [2].
But we know that the human body is a super biochemical reaction furnace, which can occur tens of millions of biochemical reactions in a second in a cell, and has its own homeostatic average regulation mechanism. If you add a supplement to the human body, whether it will be metabolized by the human body, and whether it can achieve the expected effect, there is a big question mark.
Although there have been many related studies, the molecular regulation mechanism of NAD+ precursors and related aging biology still need more in-depth research, and the current drugs related to NAD+ precursors are basically only used as a potential treatment [3].
If a drug with clear pharmacokinetics is 1+1=2, then the NAD+ precursor is still at 1+? =？ of stages.
In the case of NMN, the three geneticists who won the Nobel Prize in Physiology or Medicine in 2017 discovered the important role of NMN in regulating the biological clock and restoring circadian rhythms.
However, in terms of anti-aging, in-depth research is still needed [4], although the anti-aging effect of NMN in mice is basically determined [5], but the key evidence of NMN conversion to NAD+ [6], there is still unresolved controversy [7][8].
But overall, the potential therapeutic role of NMN as an anti-aging is not controversial.
Finally, let's take a look at this study from the Chinese Academy of Sciences [9].
We know that the NAM to NMN conversion process is catalyzed by NAMPT (niacinamide phosphoribosyltransferase). The study of the Chinese Academy of Sciences found that a low dose (about 10ng) of nicotine can enhance the NAMPT activity of elderly mice, so that it can theoretically increase the level of NAD+ through NMN remediation, thereby theoretically playing an anti-aging role.
Changes in NAMPT activity in the cerebral cortex, hippocampus, heart, liver, muscle, kidney
Through the remedial approach, the research team proved that the reversal of high glucose metabolism by low-dose nicotine in aging mice can promote neurogenesis and inhibit inflammation in old mice, improve cognitive ability in old mice, and delay NAD+-recession-related systemic aging.
Reversal of hypermetabolism of glucose in the brain, systemic and heart
And this process does not depend on the activation of nicotinic acetylcholine receptors in the brain, which means that there is no addiction, nor does it have beneficial or harmful effects associated with the nicotinic acetylcholine pathway.
Although the specific molecular mechanism is not yet known, this breakthrough discovery still deserves to be published in Nature Communications.
In fact, this study is indeed enough to prove that low-dose nicotine can be used as a potential treatment for anti-aging.
However, the health of the human body depends on the balance of a large number of biochemical substances in the human body.
Disruption of the balance can also threaten health.
The research team, also very responsible, clearly stated:
When the balance of NAD+ in the body is disrupted, it can lead to a higher risk of cancer. High levels of NAMPT expression and high NAD+/NADH ratios may lead to the risk of corresponding lesions such as tumors.
Therefore, researchers do not recommend long-term high-dose supplementation of NAD+ precursors, including nicotine.
In fact, any highly toxic substance, when low enough, can become a potential drug. And any harmless substance (or drug), when the dose is high enough, can become a poison.
Seeing the first part of this paper, intending to prolong life through smoking or e-cigarettes is equivalent to seeing that lead, mercury, arsenic aluminum and other metals have special physiological effects at low doses, and then ingesting a large amount, which leads to a huge threat to health.
In fact, in various studies, nicotine has always been a role of both good and evil. There is evidence of both health hazards and health benefits [10][11]. But without exception, high doses of nicotine are harmful to the human body.
The nicotine content in cigarettes reaches 1.5-3mg, and the nicotine used by the research team is 1~100ng, especially 10ng. For an old bong, who smoked a lot a day, nicotine intake could reach 1,000 times the dose used by the research team.
What's more, for cigarettes, the biggest killer is not nicotine, but tar. As early as 70 years ago, the carcinogenicity of tar was hammered [12]. About 10mg tar amount, dozens of carcinogens, cigarettes pose a fatal threat to health.
For electronic cigarettes, in addition to high content of nicotine, electronic cigarette vapor also contains a small amount of harmful substances, although the harm is much lower than tar, but its harm can not be ignored [13]. For smokers who are difficult to quit smoking, e-cigarettes as a cigarette substitute can indeed reduce the harm to health. But the threat to teenagers, e-cigarettes can not be ignored.
At the end of writing, I would like to emphasize:
The Chinese Academy of Sciences paper is rigorous, and there is no mention of e-cigarettes related to the paper. However, this anonymous questioner bound the research results of the paper to the content related to e-cigarettes.
I don't want to speculate on the questioner's intentions, but this is clearly a bad direction for the general public.
The CAS paper clearly states that high doses of nicotine may cause the body's NAD+ balance to be disrupted, thereby threatening health. Moreover, the nicotine dose in the Chinese Academy of Sciences study can not cause nicotinic acetylcholine-related reactions, but the nicotine in e-cigarettes is born for addiction.
That is to say, although they are all nicotine, the research that e-cigarettes are less harmful than cigarettes, and the anti-aging of low-dose nicotine, are completely different fields, and the two do not intersect.
However, for ordinary people, seeing the "Nature Communications" paper of the Chinese Academy of Sciences, and then seeing the description of the question, there will be a potential authoritative orientation: nicotine is harmless, and smoking e-cigarettes prolongs life.
The so-called rumor-mongering a mouth, refuting rumors and running off legs, related articles have appeared before:
In general, this paper by the Chinese Academy of Sciences does have a certain positive effect in the field of anti-aging. But it does not become a good support for some health-threatening products.
reference
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^Covarrubias A J, Perrone R, Grozio A, et al. NAD+ metabolism and its roles in cellular processes during ageing[J]. Nature Reviews Molecular Cell Biology, 2021, 22(2): 119-141.
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^Mills K F, Yoshida S, Stein L R, et al. Long-term administration of nicotinamide mononucleotide mitigates age-associated physiological decline in mice[J]. Cell metabolism, 2016, 24(6): 795-806.
^Grozio A, Mills K F, Yoshino J, et al. Slc12a8 is a nicotinamide mononucleotide transporter[J]. Nature metabolism, 2019, 1(1): 47-57.
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^Yang L, Shen J, Liu C, et al. Nicotine rebalances NAD+ homeostasis and improves aging-related symptoms in male mice by enhancing NAMPT activity[J]. Nature Communications, 2023, 14(1): 900.
^Benowitz N L, Hukkanen J, Jacob III P. Nicotine chemistry, metabolism, kinetics and biomarkers[J]. Nicotine psychopharmacology, 2009: 29-60.
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^Hoffmann D H I. The changing cigarette, 1950-1995[J]. Journal of Toxicology and Environmental Health Part A, 1997, 50(4): 307-364.
^Balfour, David JK, et al. "Balancing consideration of the risks and benefits of e-cigarettes." American journal of public health 111.9 (2021): 1661-1672.