# Aging

Category: Conditions

Also known as: senescence

Aging is fundamentally a process of declining oxidative metabolism, characterized by a shift away from efficient mitochondrial energy production toward non-mitochondrial oxidation and a reduced capacity to use oxygen properly. Peat's dissertation work established that the…

10 passages · 2 authors · 1972–2024 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

Canonical page: https://bioenergeticoracle.com/concepts/aging

## Synthesis

**Aging** is fundamentally a process of declining oxidative metabolism, characterized by a shift away from efficient mitochondrial energy production toward non-mitochondrial oxidation and a reduced capacity to use oxygen properly. [Source 1, 8] Peat's dissertation work established that the changes causing reproductive senescence occur in every tissue, driven by a common set of chemical and biological processes. [Source 8] He found that aged uterine tissue often consumed oxygen at a high rate, but this was a sign of *oxygen wastage* under excessive estrogenic influence rather than efficient energy production. [Source 4, 7] The crucial distinction is that while the metabolic rate of remaining active cells does not decline with age, the mass of inert connective tissue increases, and mitochondria lose efficiency or decrease in number. [Source 1] This creates a state where **non-mitochondrial oxidation** increases as mitochondrial oxidation declines, a pattern Peat connected directly to Otto Warburg's concept of a "respiratory defect" in cancer. [Source 1, 7]

The accumulation of **polyunsaturated fatty acids (PUFA)** in aged cells is now understood to be a central driver of this metabolic decline. [Source 2] Dinkov has written that senescence is characterized by a striking accumulation of PUFA inside cells, which directly compromises the function of **cardiolipin**, the crucial mitochondrial lipid that stabilizes the inner membrane and carries electrons in the electron transport chain. [Source 2] The more unsaturated the cardiolipin, the more vulnerable it is to oxidative destruction, leading to structural disintegration and less oxidative phosphorylation. [Source 2] Peat had earlier identified that a vitamin E deficiency and excess unsaturated fat both increase oxygen consumption while producing **lipofuscin** (age pigment), a substance that consumes oxygen and fuel but produces no usable energy. [Source 4, 7] This pigment accumulates in conditions of low oxygen tension, and aged cells become increasingly embedded in dense, cross-linked collagen that creates an *oxygen-deprived environment*, further suffocating tissues. [Source 3, 8]

Estrogen excess emerges as a primary hormonal driver of aging in Peat's framework. [Source 4, 8] He observed that the effects of excessive estrogen stimulation and senescence on tissue structure were remarkably similar, both causing progressive increases in collagen deposits. [Source 1] Estrogen acts in several ways to decrease oxygen availability: it induces an NADH oxidase, stimulates iron absorption (which is involved in the peroxidation that produces lipofuscin), and synergizes with vitamin E deficiency to intensify age pigment formation. [Source 4, 5] The ratio between estrogen and progesterone controls their effects, and progesterone's role is to assure oxygen and nutrient availability while inhibiting lipofuscin formation and other aging signs by improving metabolic efficiency. [Source 4] Peat argued that many features of aging resemble an *estrogen excess* rather than the estrogen deficiency promoted by the pharmaceutical industry. [Source 4] Stress accelerates these collagen changes, apparently acting through adrenal cortical hormones and estrogen. [Source 1]

The metabolic shift underlying aging is now understood through the lens of the **Randle Cycle**, where increased fat oxidation (FAO) directly competes with and displaces glucose oxidation. [Source 10] Dinkov has explained that increased FAO is sufficient to cause cellular dysfunction and senescence by lowering the FAD/FADH ratio, creating a functional block at complex II of the electron transport chain, and generating **reverse electron flow (REF)** which produces the vast majority of reactive oxygen species during oxidative phosphorylation. [Source 10] Even saturated fats, when oxidized at the expense of glucose over the long term, can shift the redox balance toward reduction and cause the same metabolic derangements as a standard Western diet. [Source 10] This aligns with Peat's view that oxidizing primarily glucose is of paramount importance for systemic health, and that low metabolism causes oxidative stress, not the reverse as the "rate of living" theory claims. [Source 9, 10] Dinkov has stated that PUFA accumulation is the major cause of cell aging and that reversing that accumulation likely restores a cell's biological age back to youthfulness. [Source 2]

The systemic nature of aging is further evidenced by the role of blood-borne factors. Serum from young animals supports better cell growth than serum from older individuals, and the albumin in old blood is in a more oxidized state. [Source 6] Selye's experiments showed that frequent drainage of fluid from isolated tissue filaments prevented age-changes, and a gerontologist reportedly rejuvenated an old dog by repeatedly replacing its blood serum with saline. [Source 6] Peat also noted that the brain and liver regulate glucose and hormones, meaning the conditions under which those organs develop influence later functioning and account for transgenerational effects. [Source 4, 7] The proportionality between onset of sexual maturity and age at reproductive senescence is a recognized genetic and dietary phenomenon, and late maternal age is associated with earlier sexual maturity in offspring, which would be expected if accelerated sexual maturity is linked to reduced lifespan. [Source 5] Every stress leaves an indelible scar, and the organism pays for its survival by becoming a little older. [Source 9]

## People also ask

### How does polyunsaturated fat accumulation drive aging at the cellular level?

Peat and Dinkov described how PUFA accumulation compromises cardiolipin in the mitochondrial membrane, making it vulnerable to oxidative destruction, which leads to structural disintegration and less efficient energy production.

### Why did Peat consider estrogen a primary hormonal driver of aging?

Peat observed that excessive estrogen stimulation and senescence produce similar tissue changes, including increased collagen deposits, and that estrogen decreases oxygen availability by inducing oxidative enzymes and stimulating iron absorption.

### What role does the Randle Cycle play in age-related metabolic decline?

Dinkov explained that increased fat oxidation competes with glucose oxidation, lowering the FAD/FADH ratio and causing reverse electron flow, which generates most reactive oxygen species and drives cellular dysfunction and senescence.

## Related concepts

- [Oxidative phosphorylation](https://bioenergeticoracle.com/md/concepts/oxidative-phosphorylation/index.md)
- [Copper](https://bioenergeticoracle.com/md/concepts/copper/index.md)
- [Cytochrome P450scc.](https://bioenergeticoracle.com/md/concepts/cytochrome-p450scc/index.md)
- [Fertility and Infertility](https://bioenergeticoracle.com/md/concepts/fertility-and-infertility/index.md)
- [Glycine](https://bioenergeticoracle.com/md/concepts/glycine/index.md)
- [Graves' Disease](https://bioenergeticoracle.com/md/concepts/graves-disease/index.md)

## Cited passages

Passage numbers match the `[Source N]` markers in the synthesis above.

### Source 1 — Age-related oxidative changes in the hamster uterus

Ray Peat · Article · Sep 1972

> failure to implant, main embryo loss (Dreisbach, 1959; Connors, 1969) tetrazolium reduction oxygen consumption oxygen partial pressure in lumen Singhal and Valadares (1969) showed that very high levels of estrogen are required to restore ovariectomized old rats to their normal enzyme levels, which implies that high estrogen may be normal for old animals. in their mitotic response (Finn and Martin, 1969) to estrogen stimulation, however, old tissues showed greater sensitivity than did the young; residual bound estrogen might account for this, and the time allowed after ovariectomy might have differed in the two sets of experiments. Old animals have a similar high sensitivity to catecholamines (Frolkis, et 21., 1970), which also can be interpreted as the effect of a high basal level. Catecholamines have also been associated with "oxygen wastage" (Raab, et al., 1962).
>
> Metabolic rate (oxygen consumption) has long been known to decline steadily with age, although the steady state level of thyroxin in the blood (Gregerman, 1967) does not appear to change, but Shock et al. (1963) found that the loss of oxygen consumption per unit of tissue weight disappears when oxygen consumption is recalculated on a cell water basis.
>
> That is, there is a decline in the number or volume of active cells with age, as the masse of inert connective tissue increases, but there is no decrease in the rate of oxygen consumption of the remaining cells.
>
> In spite of this evidence that oxygen consumption does not ' decrease generally with age, there is some evidence that mitochondria of various tissues (e.g., liver) lose efficiency, or decrease in mumber, or both, with increasing ege (Shukla and. Kanungo, 1970; Barrows, et gl., 1960). Considering the oxidase activity of age Pigment, it is possible that non-mitochondrial oxidation increases as mitochondrial oxidation declines.
>
> Loeb (1939) has found remarkable similarities between the effect of excessive estrogen stimulation and senescence on the structure of the rat uterus. Both cause progressive increase in collagen deposits.
>
> Arvay et al. (1971) have shown that stress accelerates the collagen changes of rat tail tendon and uterus, apparently act ing through adrenal cortical hormones and estrogen.

### Source 2 — Striking accumulation of PUFA in aged cells

Georgi Dinkov · Article · Apr 15, 2020 · https://haidut.me/?p=999

> Peat has written many times about the changes that occur in “aged” cells. Those changes are virtually indistinguishable from the ones that occur in “sick” cells and are characterized by reduced mitochondrial number/size and a shift in lipid composition away from saturated and towards unsaturated fats. The crucial mitochondrial lipid enzyme cardiolipin (CL) comprises at least 20% of the lipids present in the inner mitochondrial membrane and its lipid composition determines it ability to both stabilize the inner mitochondrial membrane and proton flow across it as well as carry electrons between Complex III and Complex IV in the electron transport chain, and ensure proper structure of Complexes III, IV and even V. The more unsaturated the lipid composition of CL is the more vulnerable to attack/destruction by those electrons it carries is, and thus the more vulnerable Complexes III, IV, and V that contain CL are as well. In other words, more PUFA in the cell = more structural disintegration and less OXPHOS.
>
> Thus, one would expect that aging (and disease) to be associated with a shift in cellular lipid composition in general (and CL composition in particular) towards PUFA. However, up until now evidence for age-related changes in cell lipid composition in favor of PUFA has been sparse to non-existent. The study below changes the status quo by demonstrating that senescence is characterized by a striking accumulation of PUFA inside cells. In fact, of the 19 types of triacylglycerols present in relative abundance in aged cells compared to adult ones, every single one of those glycerol types contained at least one PUFA member. The study does not go as far as to say that this accumulation is what drives aging because the study only looked at association, not causality. However, the fact that the level of PUFA accumulation was age-dependent implies causality and the knowledge about the effects of PUFA on CL function seals the deal, at least for me. The conclusion of the study was that lipids are far from passive when it comes to health and aging and they may regulate the very process of aging itself. I will go a step further and state that PUFA accumulation is the major cause of cell aging and reversing that accumulation likely restores a cell’s biological age back to youthfulness.
>
> [references]

### Source 3 — Age-related oxidative changes in the hamster uterus

Ray Peat · Article · Sep 1972

> However, several problems exist for this interpretation, for example the relation between suppression or acceleration of sexual maturity and the onset of senescence, and also the idea that excess calories will necessarily increase the production of free radicals, which has not been. established.
>
> The literature regarding free radical concentrations in living tissue is still in an early stage, as a result of the lack until recently of equipment that could measure EPR in the presence of water. This interpretation also fails to explain the observation that the amount of vitamin E required to maintain fertility increases steadily and drastically with age, being at 59 weeks 67 times the amount required by the 10 week old rat. Verzar and Ermini's (1970) observation of poor creatine phosphate recovery in old animals is interesting in connection with the creatinuria and low tissue creatine levels in vitanin E deficiency (Houchin, 1942) and the restoration of creatine kinase activity by vitamin E administration (Matusis, 1971) and the fact that X-irvadiation also produces creat inuria (Kozaika and Andrew, 1972).
>
> Besides the functional complementarity of aging and vitamin E deficiency, there is an interesting similarity in their ability to produce lipofuscin, aging pigment", or ceroid pigment, (Kaunitz, et al., 1948). This pigment has been widely discussed as an example of intracellular crosslinking, and is assumed to be a "clinker," or product of metabolism that the cell is incapable of removing (Carpenter and Loynd, 1968). Florey (1966) has referred to the existence of this material in carp which are accustomed to Living under ice at low oxygen tension and suggests that it may serve as an alternate electron acceptor in the absence of oxygen. (It is supposed that unsaturated fatty acids can serve as electron acceptor in yeast cells in the absence of oxygen (Warburg, et al., 1967).)

### Source 4 — Generative Energy: Restoring the Wholeness of Life

Ray Peat · Book · 1994

> As I tried to understand this, I saw that several things could contribute to a high rate of oxygen consumption. Either too much estrogen, or too little progesterone could have the same effect, since it is the ratio between these hormones which controls their effects. A vitamin E deficiency increases oxygen consumption, and too much unsaturated fat has the same effect. In a vitamin E deficiency, unsaturated oils are oxidized in a way that produces "age pigment," also called ceroid pigment or lipofuscin. This pigment consumes both oxygen and fuel, but produces no usable energy. Estrogen excess synergizes with a deficiency of vitamin E to intensify the formation of this pigment. Partly, this might be because estrogen is a powerful stimulant of iron absorption, and iron is involved in the peroxidation that produces the pigment. But low oxygen concentration is what causes the iron to become active in peroxidation, and estrogen acts in several ways to decrease the availability of oxygen. It appeared, therefore, that many of the features of aging resembled an estrogen excess, rather than estrogen deficiency. The way in which estrogen prevents or terminates pregnancy seems to be by causing the uterus to consume oxygen at such a high rate that there is no oxygen available for the embryo, which has a high requirement for oxygen beginning on the day that it normally implants. The chronic or cumulative effects of estrogen, leading to formation of lipofuscin, happen to act in the same direction as estrogen itself, causing oxygen to be reduced, especially in the uterus, but in all other tissues, too (aging the whole organism). Estrogen excess can also destroy the corpora lutea, interfering with the production of progesterone. Progesterone's effect in pregnancy is to assure the availability of oxygen and nutrients for the embryo, but it also has the general effect of inhibiting the formation of lipofuscin, and of other aging signs, by improving efficiency. (Progesterone is unusual among the anti-stress steroids in having no harmful side-effects.) Although my work confirmed the other research that had been done in Soderwall's lab in the preceding 25 years, the idea that estrogen's influence appears to increase with aging, and even to contribute to the process of aging, was contrary to the doctrine that has been promoted by the pharmaceutical industry.

### Source 5 — Age-related oxidative changes in the hamster uterus

Ray Peat · Article · Sep 1972

> This enzyme function should be elevated in vitamin E deficiency if the same system is really active in both cases. A microsomal NADPH oxidase is known to increase its oxygen consumption greatly in the absence of vitamin E, and in vitro pO₂ is rate limiting in the peroxidative conversion of polyunsaturated fatty acids to a dialdehyde by this enzyme. Estrogen is known to induce an NADH oxidase. It has frequently been observed that many cells in the senescent hamster uterus are filled with pigment granules (Orsini, 1962). These granules apparently require estrogen and the absence of supplemental vitamin E if they are to form (Kaunitz, et al., 1948), Peroxidase, which is induced, or activated (Lucas, et al., 1955), by estrogen, and which is known to have an NADH oxidase function (Lucas et als, 1955; Beard and Hollander,’ 1962), may be dnvolved. (Peroxidation is being widely studied in relation to.
>
> both aging and cancer.) Catalase is apparently suppressed by estrogen, which suggests that peroxide, whatever its origin (it is universally associated with respiration, but it is not known how) is being spared for another function. In cancer, a condition similar to what is proposed here for aging exists, with low NADH combined with a "reducing environment" (Reid, 1965).
>
> The proportionality, mentioned above, between onset of sexual maturity and age at which reproductive senescence, and even death, occur, has been recognized as a genetic, as well as a dietary, Phenomenon by L. C. Strong (1969).
>
> A well-known idea (Lansing, 1952) is that late maternal age tends to shorten the life-span of offspring; this seems to be in doubt even in the case of rotifers (Meadow and Barrows, 1971). (It is interesting that vitamin E happens to be necessary for eexual reproduction even in rotifers.) There is a general belief that the effect exists in mammals, too (Lansing, 1947; Carpenter and Loynd, 1968); it is generally attributed to a higher rate of mutations in the older animal, which results in slightly defective offspring.

### Source 6 — Generative Energy: Restoring the Wholeness of Life

Ray Peat · Book · 1994

> In Raymond Pearl's version, this limit was governed by heredity, and was originally demonstrated by showing that different individual organisms could survive total energy deprivation for different lengths of slow metabolism postponed starving.) (Obviously, starvation has no logical connection with aging.) Later, Pearl argued that more intense activity accelerated aging. There are now many people who argue that a low metabolic rate, a low body temperature and slow heart beat indicate that you should live a long time: "your heart can beat only so many times." Most of these people also advocate "conditioning exercise," and they point out that trained runners tend to have a slow heart rate. (Incidentally, running elevates adrenalin, which causes increased clumping of platelets and accelerated blood clotting. Hypothyroidism--whether preexisting or induced by running--slows the heart, raises the production of adrenalin, and is strongly associated with heart disease, as well as with high cholesterol.) Early in the century, Alexis Carrell showed the importance of environmental factors in the aging process, by keeping chicken cells alive and functioning for many years beyond the chicken's normal life-span. In 1927, German researchers reported that a fat-free diet prevented the occurrence of spontaneous cancers in rats. Since, a little later, other workers found that the elimination of unsaturated fats from the diet not only prevented cancer, but also caused a large increase in the metabolic rate, it might have been possible to conclude that it is not living which kills us, but something in the environment. Some people did draw that conclusion, but research funds go mainly to product-oriented research, and "the environment" has been hard to package as a product. Carrell's work involved frequent changes of the fluid that the chicken cells were growing in. Later, Hans Selye did an experiment in living rats that seems to relate to the importance of frequent changes in the growth medium. Selye implanted glass tubes under rats' skin, and found that they were soon encapsulated by fibrous tissue, and that a filament of tissue then grew down the tube, joining the membranes at the ends. When left undisturbed, this filament, isolated from the circulatory system, underwent very rapid aging. But when Selye drained the fluid at frequent intervals, the age-changes were prevented, and even when the rats died of old age, the filaments still appeared to be young.

### Source 7 — Generative Energy: Restoring the Wholeness of Life

Ray Peat · Book · 1994

> Since the brain and the liver regulate the amount of glucose and hormones in the body, the conditions under which those organs develop will very likely influence their later functioning, and account for some of the transgenerational effects that have been observed.
>
> #### Mechanisms of Aging
>
> As I became aware of the influences of hormones and the availability of energy on the development of the brain, and the effects of the brain on aging (and became aware of the amount of dogma in the neuro-sciences), I began to work on the ways in which energy metabolism affects reproductive failure, especially in senescent decline of fertility. [hoped that working in a less dogmatic area of physiology would still allow me to get a better understanding of the organism in general, including the brain. Professor Soderwall and his students at the University of Oregon had shown that the corpora lutea (areas in the ovary which mainly produce progesterone) appeared to fail in aging hamsters, and that vitamin E supplements could extend fertility by a significant amount. His group showed that "aged ova" were not responsible for infertility, but rather that the uterine environment was not suitable for implantation. Soderwall had also demonstrated that excess estrogen could cause failure of the pregnancy at any point, from failure of the embryo to implant, to resorption of the fetus at a late stage of pregnancy. Although I had investigated the association of estrogen with cancer, and knew from my own experience with migraines that stress, diet and hormones interacted in powerful ways, when I began to investigate the oxidative metabolism of the uterus I didn't realize that it would involve a convergence of several of my main interests. I was familiar with Otto Warburg's famous idea that cancer is caused by a "respiratory defect," and I knew that aged tissue has a diminished respiratory capacity. The text-books indicated that estrogen deficiency and "aged ova" were responsible for senescent infertility. (The origin of these ideas in a dogmatic matrix is another story which I have told elsewhere.) I found that the uterine endometrium of old animals often consumed oxygen at a high rate, and showed other signs of being under the influence of excessive estrogen. As I tried to understand this, I saw that several things could contribute to a high rate of oxygen consumption. Either too much estrogen, or too little progesterone could have the same effect, since it is the ratio between these hormones which controls their effects.

### Source 8 — Ask the Herb Doctor: Heart I

Ray Peat · Interview · May 17, 2013

> **Ray Peat:** From 1968 to 1972, I was in graduate school at the University of Oregon. I did my dissertation on reproductive aging and how oxidative metabolism changes with age. I found that the changes causing the menopause equivalent in animals happen in every tissue in the body. It just happens that the uterus is where I did my dissertation work, but I was interested in aging changes in the brain and bones as well. It turns out that the same chemical and biological processes change through time in all of these tissues. In my dissertation, one of the aging theories that I talked about was the collagen theory of aging: that estrogen excess causes wastage of oxygen, basically suffocating tissues the way radiation would, and destroying the ability to use oxygen. As a result of that, excess collagen is produced by the collagen-producing cells (fibroblasts) in the connective tissue. With aging, the collagen becomes progressively denser and more cross-linked, creating an oxygen-deprived environment. My emphasis at that time was on how estrogen, produced by irritation or aging, causes more collagen to be produced and to become more dense, creating further interference with oxygen consumption.

### Source 9 — #39: Low Testosterone and PUFA | Vitamin D is Anabolic and Anti-Cortisol | High Metabolism and Aging

Georgi Dinkov (with Georgi Dinkov) · Interview · Nov 15, 2020 · https://open.spotify.com/episode/1ydUK0ut0jy7L37VbyLUmX

> **Danny Roddy:** Yeah, I think when you say aging to a, if you say, oh, aging causes all disease, it's too, like, amorphous of a topic, and, like, the general layperson doesn't understand what that, it's, like, too nonspecific, you know? But, I mean, obviously, I think...
>
> **Georgi Dinkov:** Well, translated would be low oxidative metabolism, right, would cause... And then even a mainstream doctor will agree that metabolism drastically declines with aging. They're not going to deny that. They'll just deny the causative connection. They'll say, yeah, metabolism declines, but it doesn't mean that low metabolism is causing aging. Well, Anderson Horowitz is saying, it looks like it's leaning in that direction because there's nothing else that we know of. The connection at this point is basically the causation is from low metabolism to aging, not the other way around.
>
> **Danny Roddy:** I'll just read this Selye quote. It says, aging itself and particularly premature aging is in a sense due to the constant and eventually exhausting stresses of life. That was actually not the quote. There was one article that was very similar to that one. You know what I'm talking about? This was a quote I was actually thinking of. Every stress leaves an indelible scar and the organism pays for it, pays for its survival after a stressful situation by becoming a little older. So every stress leaves a scar and that organism pays for it. There was one article that talked about metabolism and aging. It's tightly close to this one. Low, not high metabolism. Oh, yeah.

### Source 10 — Increased fat oxidation (FAO) sufficient to cause senescence/aging/disease

Georgi Dinkov · Article · Nov 1, 2024 · https://haidut.me/?p=2710

> Medicine now recognizes such metabolic derangement in cancer, but claims that the ETC blocks are due to external agents, cancerous mutations, or just aging in general. But the study below makes it quite clear that the truth is actually backwards and that all that it takes for the “cancer” metabolism to occur is simply a sufficient shift from oxidation of glucose towards FAO, as per the Rande Cycle. This increased FAO results in lowering of the FAD/FADH ratio and thus a functional (co-factor deficiency) block at complex II of the ETC, which ultimately leads to the electron buildup, REF and thus drop in NAD+/NADH ratio as well. In contrast, oxidizing mostly glucose does not generate REF (since it does not lower the FAD/FADH ratio) and when the electrons flow forward it accounts for less than 2% of the total generated ROS during OXPHOS (the other 98% being generated as a result of REF). In other words, all that it takes for both function and structural pathological changes to occur, as well as senescence/aging, is increased FAO at the expense of glucose, which results in a shift of the redox balance in favor of reduction, forming a vicious metabolic cycle.
>
> An interesting finding of the study is that saturated fats (SFA), despite being much preferable than PUFA for oxidation, are also capable of affecting the Randle Cycle and shifting the redox balance in favor of reduction. The specific lipid used in the study to increase FAO at the expense of glucose was octanoate (caprylic acid), and providing sufficiently high concentrations of that SFA was sufficient to trigger the increased FAO and cause senescence. Ray mentioned this on a few podcasts when people asked him if keto diets would be OK if one ate 100% saturated fat. His answer was that a diet which contains only saturated fats in its lipid fraction is preferable to a “standard” Western diet (i.e. 30%+ PUFA on average), however long term consumption of a keto diet with 100% SFA in its lipid fraction is also not optimal since it would generate less CO2, more ROS and ultimately cause the same metabolic derangements as a standard Western diet. Thus, he said, oxidizing primarily glucose is of paramount importance when it comes to systemic health.

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