
UPFs linked to impaired fertility
How ultra-processed foods affect fertility: A summaryUPFs have been linked to reduced sperm count and motility Falling global fertility levels have coincided with the rise of UPF consumptionUPFs are linked with the reduction of reproductive hormones such as testosterone UPFs are linked to the presence of phthalates, which have in the past been connected with reduced fertility UPFs are also linked to higher weight gain than unprocessed foods, even with equal calorie intakeUltra-processed foods (UPFs) are often associated with negative health outcomes.
They have been linked to cancer, cardiovascular disease and even Parkinson’s disease. The World Health Organisation (WHO) has connected them to millions of deaths in Europe alone.
Now, a new study is linking them to reduced fertility in men, and a negative impact on metabolic and reproductive health.
Fertility declines worldwideA global decline in semen quality may sound like a conspiracy theory, but it is, in fact, a reality.
Since the 1970s, sperm count has declined worldwide by around 60%.
Suspected causes include increased body weight, intake of saturated and trans-fats, and endocrine-disrupting chemicals of industrial origin, all of which are linked to UPFs.
Fertility has also taken a dive at the same time as global UPF consumption levels have ballooned.
At the moment, it is unknown whether such a correlation is also a cause, or whether it is simply a coincidence. The study explored the connection between the two things.
Comparing UPF with unprocessed dietThe study compared those consuming a diet of mostly unprocessed foods with a diet of UPFs. Two variations of each were compared: those on a diet of adequate calories and on a diet of excess calories.
Notably, the study provided a fixed number of calories for the UPF and non-UPF diets, and were similar in macronutrient composition (although the UPF diet contained higher levels of cholesterol, saturated fat, added sugars, refined grains, and dairy products and lower levels of fibre).
Thus, the study was able to gauge the effects of the ultra-processed nature of the food, rather than its calories or even its macronutrient content.
UPF consumption leads to sperm count decline and lowers reproductive hormonesThe UPF-consuming group saw sperm count and sperm motility (ability to move) reduced, and a reduction in reproductive hormones such as follicle-stimulating hormone (FSH) in the excess calorie arm of the study. In the adequate calorie arm, testosterone was reduced.
However, lower levels of lithium and mercury were found in those on the UPF diet. Both of these have been linked with negative effects on fertility in the past.
The presence of phthalates in UPFs was speculated to be one reason why this may be the case. Phthalates have been linked to reduced fertility in the past.
Body weight gain greater for UPFsAlongside the negative impact on fertility, the study found that those on the UPF diet also gained significantly more weight than those on the unprocessed diet.
This, the study said, represented an “uncoupling” of energy intake and weight gain, which was instead linked to the ultra-processed nature of the food itself.
This could be down to a number of factors, the study suggests, for example the lower levels of metabolisable energy compared with unprocessed foods.
Furthermore, the hormonal changes resulting from diet could have altered the metabolism of the participants.