Pregnancy and Postpartum Fatigue

Metabolism – How Your Cells Make Energy
Information from the book “A Natural Guide to Pregnancy and Postpartum Health” by Dr. Dean Raffelock

 

Metabolism

One of the most common postpartum symptoms is a lack of energy. While some fatigue is certainly par for the course, debilitating fatigue – such that day after day you feel you cannot even get out of bed – is not. Some women say they are absolutely exhausted and yet cannot sleep at night, even while their babies are sleeping. We have found that many women who lack energy also complain about weakness in their muscles and a rapid heart rate. The good news is that many women who thought their fatigue was normal have been surprised at how much more energetic they can be with a few nutritional and lifestyle adjustments.

Let’s go down to the cellular level and examine what happens there to drain your energy reserves. This may sound complicated at first, but hang in there and you will discover why it is so important to get the right nutrients to maintain your energy.

Where does your body get energy from?

You probably know that the food you eat is metabolized, or burned,” in your body to make energy. The foods you eat are broken dow n into their most basic components in your digestive system, or gastrointestinal tract. These basic nutrient components amino acids from protein foods, glucose (sugar) from carbohydrates, and fatty acids from fats are then absorbed into tiny blood and lymphatic vessels that line the intestines. The nutrients then either pass through the liver or circulate in the bloodstream until they are taken up by cells that need fuel. Vitamins, minerals, and other micronutrients (nutrients that take part in bodily processes but are not burned for energy) are absorbed and circulated in a similar way.

Important parts of the metabolic process then happen in microscopic power plants called mitochondria that exist in almost every cell in your body. About 2,500 mitochondria sit within each kind of cell in the body (except for red blood cells), and some cells can increase the numbers of mitochondria they have if the body perceives a need for more energy. For example, muscle cells create more mitochondria over time if you increase the energy demands on the muscles with an aerobic exercise program.

Energy is produced in the mitochondria by the breaking apart of the bonds that hold fuel molecules together. That energy is stored in the form of a molecule called adenosine triphosphate, or ATP, and is released as needed by the splitting apart of the ATP molecule into adenosine diphospate (ADP) and inorganic phosphorus. Think of ATP as the workhorse of the cell, supplying the energy for whatever cellular work needs t o be done. For a muscle cell, this could be contraction; for an immune cell, it could be killing off bacterial invaders; for one of the cells that make up the intestinal lining, it could be bringing nutrients into and out of the bloodstream.

This conversion of food to energy is driven by a series of chemical reactions driven along by enzymes –complex molecules that regulate the rate of chemical reactions in the body. Micronutrients such as vitamins and minerals act as coenzymes and cofactors in the mitochondria, working alongside the enzymes to keep energy production going.

Figure 3.1 is a diagram that represents the metabolic processes that takes place in the mitochondria. It may look complicated at first, but as you read on, you will find that it is simpler than it looks.

Every fuel that goes into your body protein, fat, or carbohydrate is eventually transformed into a single substance, called acetyl coenzyme A (acetyl co-A) (5), before it is metabolized in the mitochondria. This allows these three different types of fuel to enter the same mitochondria1 energy making process. To become acetyl co-A, glucose (blood sugar) undergoes a process termed glycolysis (2), fats undergo beta-oxidation (3), and proteins undergo dearnination (1). The resulting acetyl co-A is a fuel that is transformed into ATP through the processes of the citric acid cycle and the electron transport chain. Once all of this has taken place, metabolic waste, in20the form of carbon dioxide and water, is all that is left of the fuel that started out as (hopefully) a nutritious meal.

In glycolysis, molecules of glucose are transformed into substance called pyruvic acid, or pyruvate. This process does not require oxygen, and so is called anaerobic (without oxygen) metabolism. This transformation, which requires the presence of vitamins B1, (thiamin) and B3, (niacin), yields two units of ATP (physiological energy) and leaves behind two molecules of pyruvate for each available molecule of glucose. Glycolysis produces energy quickly but inefficiently. Anaerobic metabolism is like trying to keep a fire going with nothing but tiny twigs. The flames up quickly, but go out quickly. Glycolysis — anaerobic energy production is often involved in the fight-or-flight reaction, a response to stress that mobilizes the body for a very fast expenditure of energy. The classic fight-or-flight example is that of a person who encounters a predator, such as a lion, in the wild — and who must then immediately either run from or fight the danger. Anaerobic metabolism helps to provide the quick energy release that helps us to respond to emergency situations. After the emergency is over, the body should be able to return to aerobic metabolism for he majority of its energy.

Approximately 90 percent of the body’s energy production should be aerobic, taking place within the mitochondria. Assuming the conditions are right, the end result of glycolysis — pyruvate — is first converted into acetyl co-A. (If the cells do not have enough oxygen available, however, they may convert pyruvate into another substance, lactic acid [lactate], which is usually involved in anaerobic energy production.) Acetyl co-A enters into the series of biochemical reactions known as the citric acid cycle, or Krebs cycle, and the electron transport chain (ETC). Here it is acted on by several enzymes and nutrient coenzymes to generate energy in the form of ATP. By the time the cycle has run its course, all that is left of the original molecule of glucose is carbon dioxide, water, and thirty-six units of ATP. This portion of the energy production process is aerobic — in other words, it requires oxygen — and it is obviously much more efficient than glycolysis, since it yields thirty-six ATP units for each original glucose molecule, while glycolysis yields only two. In addition to oxygen, the citric acid cycle requires the presence of adequate amounts of certain nutrients, among them vitamins B1, (thiamin), B2, (riboflavin), and B3, (niacin); lipoic acid; pantothenic acid; the minerals iron, magnesium, manganese, phosphorus, and sulfur; and the amino acids arginie, aspartic acid, cysteine, glutamic acid, glutamine, histadine, isoleucine, methionine, phenylalanine, proline, tyrosine, and valine. The electron transport chain, which is the other energy (ATP)-producing metabolic pathway within the mitochondria, helps to produc e another three units of ATP. This process requires the presence of coenzyme Ql0, magnesium, zinc, and vitamins B2, B3, C, and K.

Another nutrient, called carnitine, serves as a sort of shuttle for fatty acid molecules, transporting them cross the membranes that surround the mitochondria so that they can be transformed into acetyl co-A and used for aerobic metabolism. Carnitine is made in the body from the amino acids lysine and methionine, with the help of iron and vitamins B2, B6, and C.

Now you can understand why nutritional deficiencies can affect one’s energy and sense of well being at the most basic level.

Aerobic energy production is the slow-burning counterpart to anaerobic energy production — the big logs on the fire that take a little longer to catch but that last for hours. You need the twigs to get those logs going, how ever, just as you need glycolysis (or deamination, or beta-oxidation) to make aerobic energy in the mitochondria.

The conditions are right for aerobic metabolism when all of the nutrients needed for the citric acid cycle and electron transport chain are readily available. If they aren’t, the cell can still make energy through glycolysis — the first step shown in Figure 3.1. The problem is that this only creates two units of ATP from each original glucose molecule rather than the thirty-six made via the citric acid cycle and the three from the ETC. This is important bec ause mitochondria1 energy production shifts into this less efficient mode when the nutrient cofactors necessary for aerobic metabolism are not present in adequate amounts. Another way to look at this is that if the body lacks the necessary nutrients to fuel these metabolic pathways, fewer mitochondria are able to produce the high amounts of ATP that the citric acid cycle and electron transport chain yield.

The Far Reaching Effects of Inefficient Energy Production

When the mitochondria produce energy inefficiently, the adrenal glands and thyroid gland pump out more of their hormones in an effort to get more fuel to the cells. While this will give you energy, it is not the kind of energy that feels good; it is a “fight-or-flight” kind of energy that feels stressful and further depletes your body. (A more detailed discussion of adrenal and thyroid hormones appears in Chapter 9.) Your muscles, which are your body’s main storage depot for glucose, become depleted as the adrenal and thyroid hormones cause them to give up their stored fuel to be burned by cells throughout the body.

The brain has an especially high requirement for glucose; along with the red blood cells (which carry oxygen through the bloodstream); it uses up about 65 percent of the glucose circulating in the blood. If your body is burning glucose inefficiently, your brain may not get as much glucose as it needs, possibly leading to the “brain fog” that is so common in new moms, and that is often c halked up to sleep deprivation.

If pyruvate, the end product of glycolysis, is not transformed into acetyl co-A and handed on down to the processes of aerobic metabolism, it is transformed into lactic acid. This can happen due either to anaerobic exercise — exercise that raises the heart rate too high — which causes the body to burn glucose, or to a deficiency of the B vitamins required to convert the pyruvate into acetyl co-A and move it through the citric acid cycle and electron transport chain. The presence of excessive levels of lactic acid in the body can have a number of different effects. Lactic acid buildup stimulates the adrenal glands to produce the stress hormone cortisol, leading to even more losses of glucose from the muscles, more glycolysis, and less aerobic energy production in the cells. Excessive cortisol production in turn also induces the body to break down tissues and reduce the production of other important hormones and of the neurotransmitter serotonin all of which can have negative effects throughout the body as well as on mood. Lactic acid buildup also causes a distinctive fatigued sensation in the muscles — you may have felt the “burn” of lactic acid buildup in your muscles during heavy exercise.

A subtler, chronic form of lactic acid buildup can occur if the nutrients your mitochondria need for aerobic metabolism are scarce. If you tend to awaken in the middle of the night and have trouble going back to sleep, lacti c acid buildup could be the cause. Fatigue, the shakes and sweats of low blood sugar (hypoglycemia) and cravings for sweets all can be signs that your cells are using up your body’s glucose stores too quickly. Many people with chronic fatigue syndrome, fibromyalgia, and physiologic depression have problems with lactic acid buildup.

Medical research has linked chronic fatigue syndrome, fibromyalgia (a mysterious chronic muscle pain syndrome), migraine headaches, heart rate irregularities, and diabetes to mitochondria1 dysfunction. Our clinical experience has shown that supplying plenty of the right nutrients can do wonders for postpartum fatigue by supplying the mitochondria with the fuel they need to burn energy efficiently. (In later chapters, you will find guidelines for increasing your intake of these nutrients with diet and supplements.)

Controlling Free Radical Production

Just as your car makes toxic exhaust during the process of fuel combustion, the mitochondria make their own potentially toxic byproducts in the process of metabolism. These byproducts are free radicals, and they can do significant damage in the body if produced in excess, or if the body is unable to remove them safely. Free radical production is escalated under certain circumstances, such as when your immune system goes on the attack (either against harmful organisms or, in the case of autoimmune disease, against the body’s own tissues), when your liver filters out and disposes of toxic substances, or when you are under a great=2 0deal of physical or emotional stress. Free radical overload is thought to play a role in causing many, if not most, chronic and serious diseases, including cancer, heart disease, and Alzheimer’s disease, as well as in the aging process.

Your body employs substances known as antioxidants to protect it’s self against free radicals. Vitamins C and E and beta-carotene are well-known antioxidants found in the foods you eat. Dozens of other antioxidants are found in healthy foods as well. Study after study has shown that people who eat diets rich in antioxidants are healthier than those who do not. A shortage of these nutrients allows excess free radicals to age you prematurely, inside and out. (Dietary measures to increase your supply of antioxidant nutrients will be discussed in Chapter 5.) Your body also makes its own antioxidants, including the enzymes glutathione, superoxide dismutase, and catalase, and coenzyme Q10.

However, it can produce these substances only with the aid of certain nutrients from foods, including the amino acid cysteine and the minerals selenium, manganese, copper, zinc, and iron. If the supply of any of these nutrient precursors (building blocks) is insufficient, antioxidant production suffers and free radicals can begin to build up and cause damage.

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