Mitochondria, cellular energy and metabolic health

Fatigue that does not resolve with rest is one of the most frequent reasons for consultation in the Longevity pathways at Image Regenerative, in Milano as well as St. Moritz.

When routine examinations are within normal range, the question shifts to a deeper level, that of the cells' ability to produce energy.

This is the territory of mitochondria, and it is precisely from here that growing interest arises toward molecules such as NAD and its role in longevity. It is worth understanding what we truly know about these organelles, distinguishing established physiology from circulating promises.

What are mitochondria and how do they work

Mitochondria are organelles present in nearly all cells of the organism, in highly variable numbers: a few dozen where energy requirements are modest, several thousand in cardiac muscle cells, liver, and nerve tissue, that is, where energy demand is continuous.

One of their characteristics makes them unique in the cellular landscape: they possess their own DNA, distinct from that contained in the nucleus, which is transmitted maternally. This is a detail that has opened one of the most fascinating hypotheses in evolutionary biology, according to which mitochondria would derive from ancient bacteria that entered into symbiosis with progenitor cells and never separated from them.

Structurally, they are delimited by two membranes. The outer one separates them from the rest of the cell, while the inner one folds into numerous creases that multiply the available surface area: it is precisely on these folds that the structures responsible for energy production are located. This architecture explains why even a small modification in membrane integrity quickly translates into a loss of efficiency.

Mitochondria as cellular energy powerhouses

The most well-known function of mitochondria is the production of ATP, the molecule that the organism uses as energy currency for every process, from muscle contraction to nerve impulse transmission to protein synthesis.

The process is called oxidative phosphorylation. In essence, nutrients from food are progressively broken down and the resulting electrons travel through a chain of transporters located on the inner membrane. This passage generates a gradient that is then converted into ATP, with oxygen acting as the final acceptor. This is why breathing and eating are two sides of the same mechanism.

A recurring image describes mitochondria as cellular power plants, and captures the quantitative aspect of their work. However, research in recent years has shown that this metaphor remains incomplete, because it attributes to them a purely executive role that the data refute. The next chapter of this story concerns precisely what mitochondria do beyond producing energy.

Mitochondria and metabolic health

The role that emerges from recent literature is that of metabolic sensors. Mitochondria integrate information coming from nutrition, the environment, and overall physiological state, and based on that information they modulate energy production, inflammatory response, and even the mechanisms that determine cell survival.

In other words, they regulate the balance between energy produced and energy consumed, adapting it to current conditions. It is this capacity for adaptation, more than absolute power, that defines good metabolic health.

The connection with nutrient metabolism is direct. The cells' ability to flexibly use glucose and fatty acids as energy sources, alternating them according to availability, depends largely on mitochondrial efficiency. When this flexibility decreases, the organism struggles to switch from one substrate to another, and alterations are observed that involve the management of sugars and fats.

In the Longevity pathway, this level is explored with objective tools. Metabolic ultrasound analyzes body composition with attention to abdominal brown fat, a tissue particularly rich in mitochondria and involved in energy regulation, while nutritional screening evaluates the status of essential vitamins, minerals, and antioxidants.

It is worth focusing on brown fat, because it is the most immediate demonstration of how much the quantity of mitochondria affects the metabolism of a tissue. Unlike white fat, which stores energy, brown adipose tissue dissipates it by producing heat, and owes this capacity precisely to the high mitochondrial density that characterizes it. Its presence and distribution therefore tell something about the metabolic profile of the person that body weight alone leaves invisible, and justify the attention given to it during assessment.

Mitochondrial dysfunction and aging

With advancing age, alterations in mitochondrial function are observed, and these alterations appear with particular evidence in pathological conditions.

The mechanism described in literature takes the form of a vicious circle. Mitochondria naturally produce reactive oxygen species as a byproduct of their work; when the organism's antioxidant systems struggle to keep pace, oxidative stress damages the membranes and mitochondrial DNA. Damaged mitochondria work worse and generate more free radicals, fueling the process. Added to this are a low-grade inflammatory condition and a progressive loss of metabolic adaptability, that is, precisely that flexibility that represents the distinctive trait of healthy metabolism.

The corresponding clinical picture is nonspecific and therefore difficult to frame:

• Fatigue that rest does not resolve.

• Reduced resistance to exertion.

• Difficulty concentrating.

• Slower recovery after physical activity.

These are signals that deserve medical investigation, because they are shared with numerous other conditions.

It must be said honestly that the relationship between aging and mitochondria remains an open field of research. We know that the two things proceed together; establishing precisely how much mitochondrial dysfunction is a cause of aging and how much it is a consequence is a question to which science has not yet given a definitive answer. Being wary of those who present it as a resolved matter is a good orientation criterion.

How to support mitochondrial function

Many simplifications circulate on this ground, and the first useful thing is to clear the field. There are no nutrients capable of turning on mitochondria as one would flip a switch. Micronutrients are necessary for biochemical processes to occur, and a real deficiency must be corrected, but an excess does not automatically produce an improvement in function.

What has solid foundations mainly concerns physiological stimulus. Regular physical activity, particularly aerobic activity and interval training, is the best-documented stimulus for mitochondrial biogenesis, that is, the production of new mitochondria and the improvement of existing ones. Quality sleep supports cellular repair processes, while chronic stress management reduces a burden that directly weighs on oxidative balance.

On the clinical side, NAD+ IV therapy acts on a precise piece of this system. NAD, nicotinamide adenine dinucleotide, is an essential molecule for cellular metabolism and for the activation of sirtuins, proteins involved in the regulation of aging and DNA repair. Activated sirtuins in turn support mitochondrial function. Since NAD levels tend to decrease with age, the goal of therapy is to restore its availability.

The cardiological examination required before starting makes a point clear: this is a medical therapy, which presupposes an evaluation and a structured clinical context.

On the oxidative balance front, glutathione works instead, the most powerful antioxidant produced by the organism. Intravenous administration is used to neutralize free radicals, support liver detoxification functions, and restore cellular energy through optimization of mitochondrial function, with an indication that particularly concerns chronic fatigue and systemic oxidative stress. Also in this case, use occurs within an evaluated pathway, because the choice between different tools depends on what the initial evaluation actually highlighted.

Mitochondria, nutrition and lifestyle

Nutrition creates a favorable context for mitochondrial function, while it does not act as a biological switch. This is a subtle and important distinction, because it separates a realistic expectation from a promise that no food can keep.

In practice, what matters is the overall quality of the dietary pattern more than individual food. An adequate intake of micronutrients involved in energy metabolism, a sufficient presence of foods rich in antioxidants, and a balanced fat profile constitute the basis. Meal timing and their distribution throughout the day also matter, because energy availability and physiological fasting phases modulate cellular turnover processes.

On the lifestyle level, the picture converges with what we know about longevity in general. Regular movement, sufficient sleep, stress management, absence of smoking, and moderation with alcohol are the levers that act on this system, and none of them requires particular technologies.

In our team's experience, the correct sequence is precisely this. Daily habits constitute the foundations and produce the most substantial part of the result; clinical support intervenes on documented deficiencies or specific objectives, within an evaluated pathway. Reversing the order, seeking in a therapy what lifestyle does not offer, leads to expensive and disappointing pathways.

Frequently asked questions

Are there supplements that turn on mitochondria?

No. Micronutrients are necessary for cellular biochemical processes to occur, so a documented deficiency must be corrected, but an excess does not automatically improve mitochondrial function. Narratives that present a single nutrient as an activator of cellular energy find no confirmation. The best-documented stimulus remains regular physical activity, associated with adequate sleep and nutrition.

What is NAD and why does it decrease with age?

NAD, nicotinamide adenine dinucleotide, is an essential molecule for cellular metabolism and for the activation of sirtuins, proteins involved in DNA repair and the regulation of aging. Activated sirtuins support mitochondrial function. NAD levels progressively decrease with age, and this decline is accompanied by reduced activity of cellular regenerative processes.

Does physical exercise really improve mitochondria?

It is the best-documented stimulus in this field. Regular aerobic activity and interval training promote mitochondrial biogenesis, that is, the formation of new mitochondria, and improve the efficiency of existing ones. The benefit requires continuity over time and is built with regularity, while isolated sessions produce negligible effects on overall metabolic capacity.

Who is NAD+ IV therapy for?

It is indicated for those who wish to counteract cellular aging and improve energy and physical and mental performance, within a personalized Longevity pathway. It involves slow infusions of one to one and a half hours, an initial cycle of three or four weekly sessions, and monthly maintenance. It requires a reviewed ECG before starting and a medical evaluation that establishes its appropriateness.