If researchers from Harvard University - Dr. Jorge Chavarro and Dr. Walter Willett - had merely published their data and encouraged additional study to validate their findings, I'd have nothing to write about today. In fact, I may have penned a quick post about the study since it did find some intriguing associations between diet and risk of infertility in women participating in the Nurse's Health Study II.
But, they didn't simply publish a paper. No, they also published a book - The Fertility Diet - that is now featured on the cover of Newsweek and also being touted in the media as the low-tech, do-it-yourself way to prevent and even reverse ovulatory infertility!
Worse though is the media advancing the findings in a way that implies the dietary strategy has been tested in infertile women!
Take a look at how MedScape opened their article - "Higher intake of monounsaturated fats; vegetable protein; and high-fiber, low-glycemic carbohydrates improved fertility outcomes in women with ovulatory disorder infertility, according to the results of a cohort study reported in the November issue of Obstetrics & Gynecology."
The data is not from women who specifically had a diagnosis of ovulatory dysfunction (irregular or absent menstruation). Rather, the data was from a cohort of women within the Nurse's Health Study II who were identified as actively trying to get pregnant during the period of follow-up data collection. That is a very different cohort of subjects than one exclusively made up of women with infertility, or a cohort designed as a comparison study of women with and without fertility issues due to ovulation!
But the thing that really irks me is the media falling all over itself to highlight one finding in particular, the supposed reduction of ovulatory dysfunction if women follow the dietary strategy outlined in the book - "their research shows that women who follow five or more of the tips could boost their fertility by up to 80 percent," is how the Boston Channel presented it.
Charles Platkin (Diet Detective) wrote, "In fact, the Nurses’ Health study showed that those who did not follow a healthy diet were six times more likely to experience infertility related to ovulation than women who did."
How about we look at the published data - let's look specifically at those cases with ovulatory disorder infertility published in the study:
Diet Score .Cases .RR (95% CI)
Q1 (lowest) _117 _1.00
Q2 _100 _0.68 (0.52 - 0.89)
Q3 _77 _0.65 (0.48 - 0.87)
Q4 _80 _0.53 (0.40 - 0.72)
Q5 _42 _0.34 (0.23 - 0.48)
Do you see a six-fold difference between Q1 and Q5? I didn't think so!
Do you see an 80% greater chance of pregnancy in those in Q5 than those in Q1? I didn't think so!
And as an aside - I don't get is how in Q4 they reported more cases of infertility, yet managed to report a lower RR? Anyone want to help me out with that one?
Anyway, I was scratching my head, trying to figure out how they came up with these incredible numbers - statistics being used to heavily promote the book right now - and they're in the study all right, in a theoretical computer model (which should be called a fantasy search for significance) run with different scenarios of possibilities, not data of real women eating in the real world!
As the researchers noted in their paper, "we calculated the population attributable risk associated with specific combinations of dietary and lifestyle factors to estimate the proportion of cases that may have been avoided had all the women in this cohort adhered to these habits."
So now, rather than state these numbers are based on computer models and are, at best, theoretical - they're promoting the book as if it's fact that the dietary strategies actually work.
And they're doing it in a way that is promoting the idea that a woman with ovulatory dysfunction can fix it herself, without medical intervention, and get pregnant on her own.
To say this is a travesty for women's health is an understatement!
Just when you think it's not possible, it really does get worse.
If the promotion of theoretical as fact isn't bad enough, here is a real hard fact that should send chills up your spine - while the majority of cases of ovulatory dysfunction are attributed to PCOS (polycystic ovarian syndrome), a large enough number are due to hyperprolactenemia, usually cased by a small tumor at the base of the brain. Yet, the book has absolutely no warning to women that a diagnosis for the cause of ovulatory dysfunction is critical before beginning the do-it-yourself diet approach.
Think about that for a moment.
Then consider that ovulatory dysfunction can also be due to disease of the pituitary, adrenal or thyroid glands. It can also be due to premature ovarian failure (premature menopause).
Without a diagnosis, you're flying blind as to cause and without any warning in the book about the many causes of ovulatory dysfunction, you may in fact be delaying critical medical intervention to resolve the problem if you simply take the book and run with the recommendations.
Oh and it just keeps going too. Also noticeably absent is any warning to women already experiencing ovulatory dysfunction that continuing to attempt pregnancy in the absence of regular menstruation is futile. In fact the book promotes the standard advice that one year of trying to get pregnant is recommended unless one is over 35, then six months of trying is appropriate before seeking a medical evaluation.
When a woman has a regular cycle, this advice is fine - when she has absent or irregular periods, she's wasting precious time continuing along and trying without a diagnosis because without ovulation there cannot be a pregnancy!
One recommendation in particular can also be problematic for a woman already experiencing ovulatory dysfunction - the recommendation to increase iron intake. You see, if the researchers who wrote the book bothered to look at the literature, they'd have learned that women with ovulatory dysfunction often have elevated stores of iron. As the researchers in the above linked study noted, "Because the periodic blood loss resulting from regular menstruation protects pre-menopausal women against excessive iron accumulation, oligomenorrhea and amenorrhea might contribute to the increase in ferritin observed in overweight and obese PCOS patients. When studying PCOS patients and control subjects as a whole, ferritin levels were increased in women with amenorrhea compared with women with regular menstrual cycles, whereas women with oligomenorrhea presented with intermediate values (means ± SD: amenorrhea 159 ± 144 pmol/l, oligomenorrhea 114 ± 95 pmol/l, and regular menstrual cycles 83 ± 51 pmol/l; F = 3.295, P = 0.040)."
Also of note is the fact that in the book they recommend reducing saturated fat intake to less than 8% of calories.
Where, pray tell, is the data to support that recommendation?
It certainly isn't in their published paper. In their published data, the women with the lowest risk of infertility not only consumed the highest level of total fat, but their intake of saturated fat was also higher than the other groups - in fact, their saturated fat intake accounted for 11.5% of calories.
But hey, let's not let the actual data get in the way of recommendations that align with the author's previous book, Eat, Drink and Be Healthy!
While we're at it, where is the data to support eating less meat? Their published data found absolutely no difference in heme iron intake between the various groups - none at all - yet they're promoting the idea that reducing red meat in the diet is going to make a difference in getting pregnant. Their data does not support this idea; and add to that this idea has not even been tested in women attempting to get pregnant, yet that doesn't stop them from making the recommendation.
Worse though (can it really get worse?) is the inclusion within the book of the politically correct idea that reducing or even eliminating red meat is better for the environment - who needs data when you can convince women to limit or eliminate red meat on emotion.
If you're a woman wanting to get pregnant, do you want to based your diet on politically correct advice or hard evidence?
Do you want to make changes to your diet based on theoretical computer models, or data from studies that have actually investigated how a change to diet improved pregnancy rates in those participating in the study?
As Albert Einstein once pointed out, "Only two things are infinite, the universe and human stupidity, and I’m not sure about the former."
Stupidity or just plain old ignorance contributes greatly to the millions of people who succumb daily to the latest or most heavily promoted "facts" generated by epidemiologist's findings concerning diet. Today it happens to be diet and fertility, tomorrow it'll be diet and aging, the next day diet and cancer.
The problem though, with such data from epidemiological studies on diet and lifestyle, remains (and will forever remain) that correlation does not imply causation. I don't know how many times that can be repeated, but it is true and will always be true. Just as it is true that eating red meat does not cause ovulatory dysfunction anymore than consuming high levels of non-heme iron prevents it. Just as consuming regular ice cream does not make you fertile anymore than restricting saturated fat to less than 8% of your calories will make you get pregnant.
That the media is heavily promoting this book only tells us one thing - they don't understand science, the scientific method, or the difference between correlation and causation. And they certainly have not read the study in full and then compared it to the book's recommendations.
No doubt the findings are intriguing, but they do not make a proven strategy or evidence-based approach to prevent or reverse ovulatory dysfunction.
What they do provide is a starting point to actually test the dietary strategies in women with ovulatory dysfunction. Until those studies are conducted, the book is merely speculation, potentially a waste of precious time or worse for a woman with ovulatory dysfunction.
On this book I have to strongly suggest taking a pass and instead do what's best - go to the doctor if you're having problems getting pregnant or have irregular or absent periods. Without a diagnosis, you're flying blind on assumptions - it's better to have a diagnosis and tackle the problem based on facts rather than guessing what's wrong. It's true that you can make changes in your diet and see improvement, just as it's true that if your ovulatory dysfunction is caused by a tumor your diet isn't going to make a difference.
Just because the book is from esteemed researchers at Harvard doesn't mean it isn't snake oil.