Dear Dr. B: I have two questions:
1. I love eating prawns. Can you please clarify for me if prawns contain good cholesterol (HDL) or bad cholesterol (LDL)?
2. When I go to my local health club, I often visit the steam room. Outside the steam room there is a sign to say it may not be suitable for heart patients. I have had quadruple coronary bypass and I am not sure whether the rise in the body temperature in the steam room is dangerous for me.
Answer: Nutritional guidelines recommend eating fish three to four times a week because it contains large amount of omega-3 fatty acids. This fatty acid may substantially reduce the likelihood of irregular heart rhythm. It helps prevent heart attack and stroke. And it can reduce the risk of dying from heart disease by almost 50 percent.
Fish and seafood in general is low on cholesterol with three exceptions – prawns, squid and fish roe. The cholesterol from our food is not classified as HDL or LDL. We just call it dietary cholesterol.
HDL and LDL are measured in humans to estimate the risk of heart disease. We have to be careful what we eat as it affects our good and bad cholesterol.
A dietitian informs me that the present consensus on prawns is that the amount of omega-3 fatty acids present in prawns will offset the amount of cholesterol in it. So we are allowed to eat prawns in moderation even in the heart healthy diet. Prawns should be steamed and not fried/deep fried or in butter as these are all worse for our heart and would stimulate increased production of bad cholesterol in the body.
So, if you love to eat prawns then cut back and eat more of salmon, sardines, trout, mackerel, and herring broiled, baked or steamed. They contain the highest levels of omega-3 fatty acids. Fish is also high in protein, vitamins and minerals. Compared to meat, it is low in calories.
About saunas and steam rooms. The heat in the sauna is a dry heat and the heat in the steam room is wet heat. These rooms are meant for relaxation. The heat makes us perspire and relaxes our muscles and relieves aches and pains.
In a Finnish sauna the human body is exposed to higher temperature than anywhere else in natural surroundings, but only for a short time. The high temperature induces many temporary physiological changes, says Dr. Lasse Viinikka, Chairman of the Finnish Sauna Society on one of the websites I visited.
The temperature of skin increases in a few minutes to over 40°C, but after the sweating has started – usually in three to five minutes – this temperature declines and starts to rise slowly again. Skin temperature is around 40°C after a 20 minute bath, says Dr. Viinikka.
The physiological effect of increased temperature results in dilatation of skin capillary vessels. This will drop the blood pressure. In order to maintain sufficient blood pressure the cardiac output increases two to three fold. This also considerably increases the heart rate. And this puts extra stress on our heart just as it does during brisk walking. So, talk to your doctor and check how much activity your heart can tolerate.
Sweating in saunas and steam rooms results in loss of fluid, sodium and potassium from our body. So it is important to maintain good fluid balance. Dehydration can increase the load on your heart as well.
Saunas and steam rooms have many physiological short-term effects, but have no permanent long term effects on health. It is only for pleasure and relaxation. So use it carefully.
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