Prostate Cancer Research Institute - General Comments on Diet

The mechanisms and benefits of nutritional
adjuncts for patients with prostate cancer

In 1981, I wrote what I considered to be the latest concepts of nutrition. Essentially all of the areas I cited have now become widely accepted. I would like in this paper to reemphasize certain areas and add new suggestions to the previous ones.

One of the most glaring errors in health care in this country and perhaps the world, is the lack of attention to the concept of "prevention". It seems that part of human nature is to deny the possibility of illness until it occurs. Once it occurs we will do and pay just about anything to regain what we lost. If our families, schools and media focused on a few of these areas, we could reduce pain and suffering and save billions of healthcare dollars.

Unfortunately, for the most part, we are a country of excess. The average American is obese and under-exercised. We orient ourselves around the TV and while watching TV we eat. A recent article in Prevention magazine noted that one easy way to reduce weight is to decrease TV time to one hour a day. The people of this country in general eat to the point of being stuffed rather than content. We also eat our biggest meal at dinner when our activity and caloric needs are the least. As mentioned in the last nutrition paper, "Eat breakfast like a King, lunch like a Prince and dinner like a Pauper." I would go further to say that one should never eat to the point of being distended but rather to feeling no longer hungry. Think French when eating. Savor your food and eat slowly. Learn to push away part of your meal and be served smaller amounts. This will also help your pocketbook.

Another way to improve health is to change the quality of what you eat. Fat is likely the culprit with the epidemic proportions of breast, colon and prostate cancer in this and other Western countries. The incidence of these cancers and others is decreased in cultures eating a low fat, high fiber diet. In Seventh day Adventists prescribing to a vegetarian type diet, the incidence of cancer in general is markedly decreased. Even in women already having a diagnosis of breast cancer, obesity is an adverse prognostic factor; i.e. women who are overweight do not respond as well as do women of normal weight.

In a mouse model of prostate cancer involving androgen-sensitive human prostatic adenocarcinoma cells (LNCaP cells) mice fed a 40.5% fat diet had mean tumor weights more than 2 times greater than that of mice fed a 21% fat diet. The slower tumor growth associated with the low fat diet occurred even after the formation of measurable tumors when the diets were changed from 40% fat to 21% fat. The 40% fat diet approximates that found in the average American male which has been determined to be 36%. Other animal studies have shown a protective effect of omega-3 fatty acids in inhibiting the growth of the androgen-insensitive DU-145 human prostate adenocarcinoma cells.¹

When you are in the market, read the labels regarding fat content. Strive for the lowest fat diet you can reach {but not <10%}*. Animal meat consumption should be avoided as much as possible. Fish, turkey and chicken should be your source of non-vegetable protein.

The majority of medical articles now suggest that we eat complex carbohydrates- starches that require digestion to break them down to simpler carbohydrates and eventually sugars. Simple sugars should be avoided. Their consumption results in jumps in blood sugar with the body reacting with insulin production and frequently hypoglycemia (below normal blood sugar). Eating complex carbohydrates avoids this. Coarse-grained breads, whole wheat and bran cereals, raw or lightly steamed vegetables, fresh fruits are all in this class. Learn to use a Wok or skillet, and when using it, try using Pam. It contains no {little}* fat. In addition, foods within a particular nutritional class may have intrinsic benefits in preventing certain illnesses. Lycopenes are one such example.

Recent studies have shown a statistically significant inverse relationship between the ingestion of tomatoes, tomato sauce, and pizza with the development of prostate cancer. In a six-year study involving 47,894 men, Giovannucci, et al showed lycopene rich foods to significantly lower the risk of prostate cancer. Men who ingested 10 or more servings of tomatoes in several forms (sauce, juice, raw or on pizza) had a 41% reduction in prostate cancer while those who ate four to seven servings per week had a 22% reduction.² Tomatoes and tomato sauce contain high amounts of lycopene, a carotenoid. Lycopene is the most predominant carotenoid in plasma, in various tissues including the prostate gland. Lycopene is the most efficient scavenger of singlet oxygen among the common carotenoids. Lycopene is not converted to Vitamin A. The major contributors to the specific carotenoids are shown below.

Carotenoid Class	Vegetable, Fruit or Fruit
b -carotene	carrots, yams, sweet potatoes, spinach
a -carotene	carrots, mixed vegetables
lutein	spinach, broccoli, kale, mustard, chard
lycopene	tomatoes, tomato sauce, pizza, tomato juice
b -cryptoxanthin	oranges

The only other food associated with a lower risk of prostate cancer was strawberries. Men who consumed at least one serving (0.5 cup) of strawberries a day had a significantly decreased risk of prostate cancer. The compound giving the red color to strawberries is not in the lycopene family.

Another study evaluated the effect of lycopene on the development of mammary (breast) cancers in a mouse model. This showed a significant suppression of tumor growth in those mice receiving a diet supplemented with lycopene. The lycopene-supplemented group showed decreases in thymidylate synthetase within the breast tissue, lower levels of serum free fatty acids and decreased plasma levels of prolactin. Interestingly, the source of lycopene was Beta-carotene rich algae called Dunaliella bardawil.³

An increased intake of dietary fiber can have many health benefits. A high fiber intake reduces the transit time of food through the intestine and is an effective therapy for constipation. High fiber intake has also been shown to decrease the chances for getting breast, colon and prostate cancer. High dietary fiber intake binds dietary fat and cholesterol in the gut thereby reducing their absorption. This effectively lowers serum levels of triglycerides and LDL (bad) cholesterol and can raise levels of HDL (good) cholesterol. In addition, fiber is filling and low in calories. A high dietary fiber intake can improve blood sugar control in diabetic patients and can lower or eliminate their need for insulin.

Fruits, vegetable and cereals are high in fiber. There are commercially available fiber bars as well as psyllium seed products and bran wafers. I would suggest taking 6 to 10 grams of dietary fiber in the form of bran wafers mixed with applesauce. Drink plenty of water when on a high fiber diet and supplement your diet with calcium, zinc and iron. Substances called phytates in the fiber will bind with these elements and possibly create a deficiency unless supplements are taken.

Salt should be minimized in your diet. Foods high in salt are frequently high in chemicals called nitrosamines which by themselves cause cancer. Salted, smoked and pickled foods are not advised. Therefore, avoid bacon and sausage and ham. These are also high in fat. High salt intake leads to water retention in many individuals and if severe, may require diuretics ("water pills") and potassium supplements.

Salt is dangerous for people with hypertension (high blood pressure). Hypertensive patients should consider using a salt substitute that is rich in potassium chloride rather than sodium chloride. Cosalt, light salt and other salt substitutes are available in the supermarket. Potassium recently has been shown to have a blood pressure lowering effect. Low potassium resulting from diuretics taken without supplementation results in weakness and lethargy. In patients with heart disease, a low potassium level can cause disturbances in heart rhythm. Excessive potassium should be avoided in patients with kidney disease or those receiving medications that result in potassium retention.

Cigarettes smoking should be totally avoided, as should the inhalation of second hand smoke. Cigarette smoke contains many carcinogens (cancer-causing chemicals) and is one of the major causes of illness and death in the world. Cigarette smoke can not only cause cancer, but is a major cause of cardiac disease, lung and vascular disease. Lung and bladder cancers are related closely to cigarette smoking. If you want off cigarettes have your physician prescribe one of the nicotine patch products to you.

Alcohol intake should be minimized to 1 or 2 ounces a day. Alcohol will wash out many of the water-soluble vitamins as well as increase the consumption of Vitamin C, zinc, selenium, magnesium, calcium and potassium. Alcohol in excess will increase fat deposits in the heart and decrease immune function. Alcohol is a toxin to the bone marrow and can cause liver injury leading to hepatitis and cirrhosis.

1. Wang Y, Corr JG, Thaler HT, et. al: Decreased growth of established human prostate LNCaP tumors in nude mice fed a low-fat diet. JNCI 87:1456-62, 1995

2. Giovannucci E, Ascherio A, Rimm E, et. al: Intake of carotenoids and retinol in relation to risk of prostate cancer. J Natl Cancer Inst 87:1767-1776, 1995

3. Nagasawa H, Mitamura T, Sakamoto S. et. al: Effects of lycopene on spontaneous mammary tumour development in SHN virgin mice. Anticancer Res 15(4):1173-8, 1995