"Treating Advanced Prostate Cancer with Diet: Part 1"
Dr. Dean Ornish showed that a plant- based diet and lifestyle program
could apparently reverse the progression of prostate cancer
by making men’s bloodstream nearly 8 times better at suppressing cancer cell growth,
but this was for early stage, localized, watch-and-wait prostate cancer.
What about for more advanced stage life-threatening disease?
There had been sporadic case reports in the literature suggestive of benefit.
A man, for example, with extensive metastatic disease,
given maybe three years to live, goes on a strict plant-based diet.
Four years later, it appears the cancer has disappeared.
Six years in, he gets a little cocky and backslides a little bit on the diet.
Cancer comes raging back and he dies.
But, that could have been a total coincidence.
That’s the problem with case reports, which are just kind of glorified anecdotes—
you have no idea how representative the outcome is unless it’s formally studied.
But throughout the 20th century, all we had were these kinds of case reports... until 2001.
So, we had this preliminary evidence based on all the case reports
that prostate cancer may be sensitive to diet even after it metastasizes,
may prolong survival and even cause remission
of bone metastases in men with advanced disease.
So, researchers decided to put it to the test, 4-month intervention.
They figured too much saturated fat, too little fiber, and too much meat
may be the biggest players in tumor promotion and progression.
So, they put people on a whole food plant-based diet
of whole grains, beans, seeds, and fruit.
Figuring this would be quite the departure from their regular diet,
they included a stress reduction component in hopes of improving dietary compliance.
Okay so, who were these ten men?
They all didn’t just have prostate cancer;
they all had underwent a radical prostatectomy to remove their primary tumor,
and then subsequently had increasing PSA levels,
indicative of probable metastatic disease.
PSA stands for prostate-specific antigen; it’s only made by prostate cells,
and they just had their entire prostates removed.
So the level should be zero.
The fact that they not only still had some PSA,
but that it was rising suggests that the surgery failed,
and the cancer had spread and was making a comeback.
Here’s where they started out before the study began.
This is a graph of the speed at which each of their PSAs was going up.
So, if after 4 months of eating healthy, the graph looked like this,
it would mean the diet had no effect.
The cancer would presumably still be powering away and spreading just as fast as before.
Instead, this happened.
In two men, it looks like the cancer accelerated, grew even faster,
but in the other 8 men, the intervention appeared to work,
apparently slowing down cancer growth,
and in three it didn’t just slow or stop,
but appeared to reverse and shrink.
Why the different responses?
Well, in the Ornish study, the more people complied
with the diet and lifestyle recommendations, the better they did.
Dietary changes only work if you actually do them.
Just because you tell people to start eating a whole food plant-based diet,
doesn’t mean patients actually do it.
One can use fiber intake as a proxy for dietary compliance,
since all whole plant foods have fiber,
and Ornish’s patients about doubled their fiber intake from 31 to 59.
How did this group do?
They started out even worse, averaging 14 grams a day,
and only made it up to 19 grams a day.
That’s not a whole food plant-based diet—
that doesn’t even make it up to the recommended minimum daily intake.
If you look closely, only 4 men increased their fiber intake at all.
So maybe that may explain the different responses.
Like, how did patient 2 do?
The man whose fiber improved the most had the best PSA result,
and the man whose fiber intake dropped the most had the worst PSA result.
Here’s the graph.
And indeed, it appears the more change they made
to their diet, the better their results.
The researchers concluded that a plant-based diet delivered
in the context of stress management may slow the rate of tumor progression,
and unlike other treatments, may give patients some control over their disease.
And, as Ornish pointed out,
“the only side effects are beneficial ones.”