Recently the New York Times published an article titled: High-fat Diet May Fuel Spread of Prostate Cancer citing an animal study looking at the relationship of fats with this male disease.
The association between dietary fats and cancer is not new. Back in the early nineteen forties, a researcher, Dr. Tannenbaum postulated that fats indeed contribute to cancer.
But back then until roughly the 1990’s, dietary fats were considered the big evil monster – the primary culprit of all deadly health problems.
Today, popular diets like the ketogenic diet are all about eating fat in the attempt to make energy from the fat byproduct, ketones, not sugar.
Let’s take a closer look at the study questioned.
• About ten mouse models were studied
• Some mice were fed a high, 60% fat diet and others a low, 17% fat diet
• Researchers observed two genes, PTEN and PML. (These genes normally protect us from cancer, and they are known as tumor suppressor genes.)
• When mice had little or no PTEN and PML genes, prostate cancer cells spread and produced fat molecules.
• When mice producing fats were given an obesity drug named “fatostatin” cancer regressed.
• This drug works by stopping the production of fat formation.
• A group of mice was then fed a high-fat diet compared to another group who at a low-fat diet and researchers noticed more tumor spread in the fat eating mice.
Does this Study Prove that Dietary Fats Fuel Prostate Cancer?
First, as you may guess, one cannot make strong conclusions from animal studies for human application. If we would, we’d have the cure for every disease by now.
Second, what exactly was in the food in the group of mice eating a high-fat meal?
I was curious to know.
Here’s what I found…
Among other things, the high-fat meal fed to mice contained non-fat components that are linked to prostate cancer; 265g Casein and Choline 3.0g
All these ingredients have been linked to prostate cancer and lard (pork fat) is probably the least culprit.
Casein, a protein found in dairy has been linked to the proliferation of prostate cancer.
Choline is a water-soluble vitamin also associated with advanced prostate cancer in studies.
To note: The low-fat feed contained no casein or choline.
Third, don’t be fooled, researchers in this study are interested in researching a drug interfering with fat metabolism and hopefully slowing down the spread of cancer, not the best diet for us to avoid or manage prostate malignancies.
Let’s Understand Fats Better
Without writing a scientific dissertation allow me to give you the skinny on fat.
Fat is one of three macronutrients in the body along with protein and carbohydrates. Notice the word “nutrient’ in macronutrient. That means dietary fat provides nutritious value and helps animals (especially humans)to grow and survive.
Simply put, without dietary fat we die.
Fats are an important component of every cell in your body giving them structure and making them semi-permeable – important in keeping water-soluble toxins outside of your cells.
Also, dietary fat helps you lose body fat. That’s right. Eating fat can likely help you lose unnecessary weight from fat.
Remember Snackwells by Nabisco back in the early 90’s? Nabisco decided to make all sorts of fat-free snacks loaded with sugar, and it did not only make people fatter, but Type 2 Diabetes also skyrocketed around that time. Now it seems like Snackwells are High Fructose Free – woohoo! Still very less optimal.
Very low carb diets higher in fat has shown to successfully lower body weight and stabilizes blood sugar levels – two things crucial in managing prostate cancer.
Lastly, eating fat makes you less hungry. So while you do eat more calories per serving when eating dietary fats, you end up eating less overall.
How does that oatmeal with banana for breakfast work you by mid-afternoon? You are starving.
Dietary fat is important for brain function because your brain is made up of mostly, you guessed it, fat.
And that’s just to name a few benefits this dietary nutrient.
In it’s strictest definition, fat is a series of carbons, single or double bonded, with a hydrogen molecule attached to each carbon molecule. On the first end of that chain you have a carboxylic acid, and on the other end, there’s a methyl group.
Depending on the length of the chain of carbons and the amounts of double bonds (or if there are no double bonds) will depend on the type of fat you are eating.
OK, maybe I geeked out a little here but here’s what you need to know; despite the conclusions of this recent mice study, it is critical for you to continue eating good quality dietary fats because it may not only protective against prostate cancer but imperative for wellness and optimal performance.
There are three main types of fat found in nature.
- Polyunsaturated fat (poly =many, thus many carbon double bonds)
broken down into omega 3 and omega 6-fatty acids
o omega 3-fatty acids are further broken down to, ALA, EPA, and DHA (actual names of these abbreviations are not necessary)
- ALA is found in plant oils like flaxseeds, walnuts, chia, hemp seeds
- ALA (α-Linolenic acid) can be converted into DHA and EPA in the body, although the rate of conversion of α-linolenic acid into EPA is relatively inefficient, at 5–10% and is inhibited by linoleic acid (omega 6-fatty acid).
- EPA and DHA are both found in marine oils. Examples, where found, include salmon, sardines, mackerel, and anchovies.
- Omega 6-fatty acids are further categorized to linoleic acid, gamma-linolenic acid, arachidonic acid and a few others.
- Oils high in Omega 6’s include, safflower oil, corn oil, soybean oil and canola oil.
- ALA is found in plant oils like flaxseeds, walnuts, chia, hemp seeds
- Monounsaturated fat (mono= one, thus one carbon double bond) are found in olives, avocados, cashews and their respective oils. Numerous other foods contain monounsaturated too.
- Saturated fat (no double bonds, every carbon is saturated with a hydrogen atom) found primarily in coconuts and coconut oil, butter, pork fat (lard) can be further broken down to lauric acid, butyric acid, palmitic acid, stearic acid, caprylic acid and mystiric acid.
So, unlike popular belief, there are benefits from eating some saturated fats as well.
Bad nutrition science and bad interpretation of nutrition science on media headlines are significant contributors to prostate cancer and premature deaths.
Is There a Connection Between Dietary Fats and the Spread of Prostate Cancer?
There is no conclusive association between eating fat, including saturated fat and prostate cancer.
With two possible exceptions: Too much Omega 6-fatty acids and trans – fatty acids.
Omega 6 fats are good for you but only when it is in the balance with omega 3-fats. The omega-6 to omega-3 ratio in the standard American (heart attack) diet is 20 or 30:1, omega 6 to omega 3. The healthier ratio is 2 or 1:1, respectively. Source.
Trans-fats or partially hydrogenated oils, as you may read ingredients lists, found in margarine and Crisco is an industrially created unsaturated fat that gets hydrogenated (synthetically adding hydrogen atoms) causing a trans molecular structure compared to the most natural cis form.
Since trans structured fats are unnatural, eating them causes havoc in the body including hardening of blood vessels (atherosclerosis) and increases systemic inflammation.
Trans fatty acids are found in virtually all processed foods, baked goods and deep fried foods.
Stay away from trans-fatty acids.
Overall, simple carbohydrates and trans-fats are public enemy number one and the two substances that most contributes to cancer, obesity, and disease-related deaths.
What do Human studies say about the connection between fats and Prostate Cancer?
The correlation between fat consumption and the risk of prostate cancer seems to depend on the specific types of fat and their constituent fatty acids.
This researcher studying close to 150 Jamaican men evaluated the relationship between the intake of dietary fatty acids and prostate cancer biopsy grade and volume and concluded that omega-6 fatty acids stimulated prostate cancer cell growth, whereas omega-3 fatty acids inhibited cancer cell growth.
This meta-analysis that studied close to 450,000 subjects showed a significant 63% reduction in prostate cancer–specific mortality, not prostate cancer diagnosis. Most fish is largely high in Omega 3-fats.
In the North Carolina-Louisiana PC Project, 322 cases out of 1800 were considered an aggressive disease. High total fat-adjusted and saturated fat intake was associated with increased prostate cancer aggressiveness, with a suggestion of a stronger effect in men not using statins.
Another study had the exact opposite results after prospectively following about 385 men for an average of five years. The saturated fat consumption was significantly associated with higher survival from prostate cancer (p = 0.008). Compared to men in the lower intake of saturated fat, those who ate more saturated fat had three times less risk of dying from prostate cancer.
The long European multicenter prospective study of 142 520 men in the European Prospective Investigation into Cancer and Nutrition (EPIC) study suggest that there is no association between dietary any type of dietary fat and prostate cancer risk.
Lastly, one study reported that consuming high amounts of fat from vegetable sources (e.g., olive oil, nuts) after diagnosis of non-metastatic prostate cancer was associated with lower risk of developing lethal disease.
Interestingly, in this same study, replacing 10% of calories from carbohydrates with vegetable fat was associated with a 29% lower risk of lethal prostate cancer. Perhaps even more interesting, Men who consumed more vegetable fat after diagnosis had a lower risk of all-cause mortality. Replacing 10% of calories from carbohydrates with vegetable fat was associated with a 26% lower risk of death from any cause.
Researchers also found a 5% increase in saturated fat was associated with a 30% higher risk of death and a 1% increase in trans fat was associated with a 25% higher risk of death.
What to make of the Studies on Dietary Fats and Prostate Cancer
Inconsistent and contradictory results from nutrition studies will continue to emerge in part because of the inherent variability of foods, as well as the uncontrolled variables in study populations and experimental designs.
In the North Carolina-Louisiana PC Project, for example, is the link between saturated fats and aggressive prostate cancer the result of eating too many cheeseburgers or pints of ice cream? I mean obesity in the South of the United States is rampant and fried chicken is a staple meal.
I do like my gumbo now and then though…
But really, we are not studying groups of people eating a tablespoon of butter (saturated fat) a day compared to another group eating a tablespoon of olive oil (monounsaturated fat) and the another taking an ounce of flaxseed oil (polyunsaturated) and then seeing what happens in ten years or so.
That would limit other variables found in fatty foods and provide clarity on what is truly causing what.
Such study, which will never happen for obvious reasons, would show insight about the type of fat that may cause prostate cancer and overall deaths and which fats do not.
Just look at the recent animal study in question at the beginning of this post. The high-fat meal wasn’t only saturated fat, it consisted of other ingredients known to promote aggressive prostate cancer. So what caused cancer spread on these fat eating mice? Was it the saturated fat? Was it the casein? What it the choline? I don’t know.
And that’s why making oversimplified conclusion in nutrition science is so challenging.
How I provide solid guidelines for patients and my audience is by:
- Tirelessly reading most of the research papers on this type of topic, not just the last published study. There is more value in the preponderance of data than the latest journal article.
- Have a good understanding of nutrition and biological science. In other words, I teach my students to learn how the body functions normally so then identifying dysfunction becomes easier.
- I am my own experiment. I simply try different diets, different supplements, different exercises and then see how I feel and look at labs results. Yes, I am my number one guinea pig.
- In my busy practice, I get to see what works and what doesn’t with patients. And see for whom something works and doesn’t.
Here are my recommendations regarding fat consumption, prostate cancer, and longevity.
- Overeating any macronutrient, protein, carbs or fat is a problem. The good thing with dietary fat is that you can’t eat too much of eat before becoming queezy. Carbs on the other hand, you can and want to keep eating for days.
- IGF-1 is produced in the body when eating large amounts of protein. Dairy, for one, increases the levels of IGF-1. IGF-I is associated with increased risk of prostate cancer and a higher risk of prostate cancer-specific mortality in men with advanced cancer. Soy proteins also raises IGF-1 levels.
- Carbohydrates, particularly those with a high glycaemic load consumed in excessive amounts result in increased fat stores due to influences on blood glucose and excess calories. This results in a state of relative hyperinsulinemia and obesity, which has been postulated to increase the risk of developing prostate cancer through higher bioavailability of circulating estrogen and IGF-1.
- All dietary fats are important to eat, except hydrogenated, trans-fatty acids found mainly in fried and processed foods. Stay away from them.
- Saturated fat is fine to eat, especially from better sources, coconut oil, Pastured butter even pastured lard. What! Lard!?
- Animal fats are not all the same, and it depends on the environment and diet of the animal. grass-fed meat has more omega-3’s and CLA ( another healthy fat) than grain-fed beefPork fat (lard) is healthier and different when pigs are pasture grazing.
“ We are not only what we eat. We are what we eat eats too.” – Michael Pollan
- The most harmful fats are polyunsaturated or monounsaturated fats exposed to heat, air or light for long periods of time. So that means frying your food in olive oil is not a good idea. Same with foods fried in canola, soy bean or vegetable oil. These oils become rancid and are cancer promoting.
- Saturated fats, on the other hand, can be exposed to heat and do not oxidize. Again, coconut oil pastured butter and even pastured lard is ok, just not too much.
- Plant-based oils and fats are protective and promote longevity. Eat walnuts, almonds, flaxseeds, sunflower seed, etc.
- Too much of any macronutrient has detrimental prostate cancer effects and interferes with longevity. That’s why I’ve become a fan of intermittent fasting as of late where you don’t eat any macronutrient for a longer period than usual, say twelve to sixteen hours a day or more.
And that’s it. For today.
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