The Life Cycle and Nutrition of Human Cells

Proteins are an important part of our food, and also serve as important building blocks for our cells.

Proteins are complex chains of smaller chemicals, which are called amino acids. There are 20 different amino acids that are used to make proteins. As we discussed last week, our DNA contains the blueprint for how to construct the different proteins needed for life from the 20 different amino acids.

Enzymes are a special kind of proteins that help promote various biochemical reactions in the body. Other proteins can serve as structural components such as collagen.

Different kinds of life (animal, plant, fungus, bacteria, etc) have different DNA and therefore different proteins. Even different individuals in the same species (e.g. humans) have slightly different DNA (genes) and therefore slightly different bodies. But all life uses the same DNA genetic code, and all life forms have many similar proteins that perform similar (not exactly the same) functions; different kinds of life also have certain unique proteins as well.

In humans, the proteins we eat are digested (mostly in the stomach) to reduce the proteins back to their simple amino acid components. The amino acids are then absorbed in the intestines to enter the blood stream, where they are used to feed the cells of our body and to make new cells.

All cells need a proper balance of all 20 amino acids to support cellular function and to make new cells.

Cell membranes separate the inside of the cell from the outside, but also support transfer of specific nutrients into the cell and waste products out of the cell.

The main feature of all cell membranes is that the are formed primarily from what is called a lipid bilayer. A lipid bilayer is formed primarily by combining many molecules that have a water-insoluble fatty acid at one end and a water-soluble phosphate group (which contains phosphorus) at the other. These are called phospholipids.

Since the fluid outside cells is mainly water, and the phosphate groups are water-soluble, the outside of the cell membrane consists of the phosphate ends of a "sheet" of many phospholipids.

Since the fluid inside cells is also mainly water, the inside of the cell membrane also consists of the phosphate ends of a "sheet" of many phospholipids.

These two sheets combine to form the lipid bilayer that surrounds all cells. The outside and the inside of both sheets consists of the water-soluble phosphate end, with the fatty acid portion of each sheet facing each other in the middle.

Various other things "float" in this basic lipid bilayer membrane, including various proteins that support transfer of specific nutrients into the cell and waste products out of the cell, as well as proteins that act as "cell receptors" that allow one cell to "talk" to another.

In animal cells (including human), cholesterol is a necessary part of cell membranes; plants have chemicals related to cholesterol, such as sitosterol and other "phytosterols" (plant steroids); fungi have ergosterols.

Most people can eat plants without problems from phytosterols, because our body normally eliminates phytosterols so that they do not accumulate. But some people have a genetic variation in their DNA that causes them to retain phytosterols, which can cause the same diseases associated with excess cholesterol. Dr. Weyrich can do genetic testing to identify this problem, and there are pharmaceuticals that can treat this condition.

But the most important point is that cell membranes require many different kinds of fatty acids, including both saturated and unsaturated fats, as well as cholesterol. But other fats, such as trans fats and oxidized (rancid) fats are harmful to cell membranes. The best saturated fats are found in butter and coconut oils. The best unsaturated fats are olive oil, avocado oil, and fish oil. Vegetable oils such as corn oil tend to have excessive amounts of inflammatory fats called omega-6 fats, and tend to become rancid easily. Trans fats are found in partially hydrogenated vegetable oils, which at one time were called healthy fats, but now are known to be the most unhealthy fats.

DNA and RNA are made from a special sugar called ribose and nitrogen-containing chemicals called purines and pyrimidines. The body can make all of these compounds if it has adequate protein nutrition, but purines are also found in foods.

Too much purines in the diet can cause problems such as gout, especially for people with a genetic variation in their DNA that causes them to retain purines.

Various kinds of cells have additional nutritional needs. For one example, cells that contain many mitochondria require an adequate supply of a substance called CoQ-10, which acts as an anti-oxidant and is also necessary for energy production in cells.

Cells that have high need for energy from mitochondria have a high need for CoQ-10. In particular, heart, muscle, liver, and brain cells require high levels of CoQ-10.

Unfortunately, statins, the most common pharmaceutical drug that is used to treat "high cholesterol," turns off the body's production both cholesterol AND CoQ-10. Muscle pain and wasting and liver toxicity are common side-effects. More controversial evidence suggests that statins also impair brain function and heart muscle function.

If you must take a statin, you should also take a CoQ-10 supplement. Talk to your doctor about dosing.