Kidney Disease and High Levels of Fatty Acids

For many patients, ongoing nephropathy leads to a disturbance of the fatty acid metabolism, with the result that the concentrations of triglycerides and cholesterol in the blood increase. From animal experiments, there is evidence that these elevated blood fats accelerate the progress of kidney disease.

Whether this also occurs in people has not yet been demonstrated convincingly. Some studies have shown that in patients with advanced nephropathy, the loss of kidney function was less when, for example, the level of cholesterol was reduced by medical therapy.

Regardless of any possible detrimental influence on the course of nephropathy, a raised blood fatty acid profile, particularly of cholesterol, leads to the development of atherosclerosis. The consequences are circulatory problems in the heart, the brain and the legs.

People with diabetes and concomitant kidney damage are especially at risk from arteriosclerotic complications of the blood vessels. It is therefore important for them to monitor the fatty acid profile in their blood.

The best-known fat risk factor for arteriosclerosis is cholesterol. It is one of the most important components of the body, needed in many places, for example for making cell walls, for the immune system which guards the body against infection, and as starting material for the synthesis of many hormones.

In addition, cholesterol forms the initial building block for the bile acids, which are essential for normal fat digestion in the small intestine. Cholesterol can be made in the body, primarily in the liver. It is also obtained from the diet, almost exclusively from foods of animal origin.

Cholesterol occurs in different forms. The two most important are LDL (low density lipoprotein) cholesterol and HDL (high density lipoprotein) cholesterol. LDL makes up the major part of the total cholesterol and is known as the ‘bad’ cholesterol, because it is deposited along the walls of the blood vessels, leading to arteriosclerosis.

HDL cholesterol, on the other hand, has a protective effect on blood vessels: it is able to absorb cholesterol from deposits on the vessel walls and transport it to the liver. There, the cholesterol is broken down and excreted via the bile. It is therefore known as ‘good’ cholesterol.

LDL and HDL cholesterol can be measured in the blood. In order to assess your risk of developing arteriosclerosis, it is important to know the concentrations of both types. The best situation is when the level of LDL cholesterol is as low as possible and the level of HDL is as high as possible.

The experts have set recommended cholesterol targets for people who have kidney damage and a concomitant increased risk of arteriosclerosis. After cholesterol, the triglycerides are the second-most important lipid in the body.

They are the most important storage compound for fats. Triglycerides are obtained mainly from the diet, but can be made and broken down in organs such as the liver or fat cells (adipose tissue).

Normal levels of triglycerides in the blood are less than 200 mg/dl. A high concentration of triglyceride is often associated with a low concentration of HDL cholesterol and therefore has a bad influence on the development of arteriosclerosis. But this is low in comparison with the effect of LDL cholesterol.

In the presence of very high levels of triglycerides, e.g. over 500 mg/dl, the blood serum, which is normally clear, becomes cloudy. This affects the fluid properties of the blood and, in the presence of preexisting narrowing of the arteries, for example in the heart or brain, can be very unhealthy.

Very high concentrations of triglycerides can also cause inflammation of the pancreas. The first step to combat raised levels of LDL cholesterol should be to examine your dietary habits, i.e. assess your daily intake of fat.

This is important and independent of whether you are going to start taking lipid-lowering drugs because, on the one hand, a small rise in the lipid profile can be treated with a change in the diet alone, while on the other hand, the effect of lipid lowering drugs can be reduced or even blocked by the wrong food!

The goal of any change in the diet should be to reduce the high proportion of fat in your food, particularly fats of animal origin. This can be done without having a major impact on your normal eating behavior. You just need to increase the amount of suitable food in your diet by a small amount and reduce the unsuitable foods.

You also need to follow low-fat methods of preparing foods. It is not enough simply to forgo your breakfast egg! You can also have a beneficial effect on your cholesterol profile by increasing your physical activity. Regular physical training increases the amount of ‘good’ HDL cholesterol.

The best activities are those that promote endurance, such as walking briskly, jogging, cycling, swimming or even skiing. It is important that these activities are performed regularly, i.e. at least three times a week for about 30 minutes each time. A short daily program is better than a mammoth program at the weekend.

The changes required to your lifestyle and eating pattern are not that great. You should be able to achieve some of them, at least in part, to back up your medical therapy. Here, we must mention smoking again. Smoking cigarettes decreases the level of ‘good’ HDL cholesterol.

Therefore, giving up smoking will help prevent arteriosclerosis by enhancing protective factors. If you cannot get your cholesterol profile into the required range through changes in diet and lifestyle, you need to start medical therapy. The most effective drugs for lipid lowering are the cholesterol synthesis inhibitors, the statins.

They block the synthesis of new cholesterol in the liver and thereby lower the concentration of ‘bad’ LDL cholesterol particularly effectively. The importance of this reduction in LDL cholesterol for the development of coronary artery disease in people with diabetes was shown in the Scandinavian 4S trial.

The risk of suffering a second myocardial infarct after an initial one was 42% lower in patients who received the statin, simvastatin, than in those who did not. If the above dietary measures are taken, the triglyceride profile will also improve.

An important factor here is excess alcohol consumption, which sharply raises the triglyceride concentration in many people. How much alcohol is allowed has to be determined for each individual. We know that alcohol, in moderate amounts, can have beneficial effects on the blood vessels.

Drinking about 20–30 g per day, which is about ¼ litre of wine or ½ litre of beer, raises the concentration of the ‘good’ HDL cholesterol. If the triglyceride concentrations cannot be lowered sufficiently through dietary control and statin therapy, fibrates or other drugs can be added to the treatment regime.

Combination therapy with statins and fibrates has possible side-effects and should be initiated only under close medical supervision. The relationship between diet and blood lipid profile has been known for a long time. The goal of any change in diet is, first, to reduce the proportion of fat in the diet, particularly animal fat.

This is easy to achieve if you follow some simple ground rules. Fats can also be reduced by preparing food in their absence or with only a little. Good methods are boiling, grilling or steaming. When baking or stewing, the amount of fat can be minimized by using special pans and baking foil.

It is not only the total amount of fat in the diet but also the type of fat that determines your lipid profile. There is a difference between saturated and unsaturated fatty acids. The saturated fats are the dangerous ones, because they prevent the uptake of LDL cholesterol into cells. They occur mainly in animal fats: meat, cheese, butter, eggs, cream, full milk and its products.

Chocolate and cooking fats also contain predominantly saturated fats. Unsaturated fats count as healthy fats because they lower the concentration of LDL cholesterol. These types of fats occur mainly in vegetable matter: vegetable oils, rice, oats or millet. Fish also contain large quantities of unsaturated fatty acids.

The dietary changes described above will lead automatically to a decrease in cholesterol absorption. Some foods contain significant amounts of cholesterol and should therefore be avoided; egg yolk, all offal, crustaceans and shellfish. An egg yolk contains a full day’s portion of cholesterol (250–300 mg)!