Is Soy Safe? Is Butter Back?

Nutrition experts encourage sifting through science and media claims with critical eyes.

Marcos Paseggi, Adventist Review
Is Soy Safe? Is Butter Back?

What follows is part of a series of reports on presentations given at the Seventh International Congress on Vegetarian Nutrition in Loma Linda, California, United States, from February 26-28, 2018. Individual stories provide a summary of various topics covered at the event. ~ Adventist Review Editors

We have all been there.

You listen, watch, or read a compelling report about the beneficial properties of a specific nutrition option on a respected media outlet. The report’s claims — it is emphasized — are backed by the latest science. You find yourself agreeing with what you see or hear—you are, so to say, ‘talked into it.’ As a ‘new convert,’ you go out immediately to purchase the advertised panacea fruit, vegetable, grain, or oil. Barely a few days later, however, you come across another health report on the nutrition item in question. The only difference is that this time, science-backed claims seem to be pointing out right in the opposite direction.

How to make sense of all these conflicting pieces of information? How to sift out fact from fiction, sound dietary suggestions from faddish baloney?

These and similar questions were not directly addressed during the Loma Linda’s International Congress on Vegetarian Nutrition in Loma Linda, California, United States, in late February 2018. On the sidelines, however, several presentations and at least one of the plenary sessions provided enlightening windows into the way science and public opinion work, including sources that inform what media outlets “buy” and we, in turn, consume.

Below are a couple of examples, as illustrated in two of the congress presentations.

Science Blues: Soy Consumption and Breast Cancer

The way science has dealt with soy consumption in breast cancer survivors is one significant example of science’s shortcomings and biases, said Mark Messina, adjunct professor at Loma Linda’s School of Public Health. Rigorous debates have weighed in on the impact of post-diagnosis soy intake on the prognosis of breast cancer survivors, he shared. First concerns were raised after rodent studies published in the 1990’s showed that soybean isoflavones stimulate the growth of existing mammary tumors in mice implanted with human breast cancer cells.

Results of studies on mice were automatically extrapolated and applied to humans, informed Messina. But to get a comprehensive picture of the topic beyond what is shared with the public, we must understand how science works. It is important to differentiate between clinical trials, especially on mice, and human data research, he said.

“No clinical trial evaluated the impact of soy consumption on breast cancer,” Messina explained. “However, considerable human data suggest that soyfood consumption by breast cancer survivors is not only safe but potentially beneficial.”

While instant conclusions on preliminary trials with mice blamed soy consumption, since then, clinical studies have shown that “soy consumption…does not adversely affect markers of breast cancer risk,” shared Messina. Unlike risky hormone combined therapies, soy consumption is not only not harmful but can be advantageous for breast cancer survivors and healthy women alike.

“Epidemiological data, which involves [more than] 11,000 Chinese and American breast cancer survivors, show that consuming soy after a diagnosis of breast cancer reduces recurrence and mortality,” said Messina. “[And] collectively, the evidence indicates soy intake recommendations aimed at healthy women are also applicable to breast cancer survivors.”

The Swaying of Public Opinion: Butter, Coconut Oil, and Other Fats

When it comes to conflicting information one might find in the media, it is essential to remember how media work, and get all the facts to make informed decisions, advised Alice Lichtenstein, professor of Nutrition Science and Policy and senior scientist at Tufts University, in Massachusetts, United States. A good example of these dynamics, she said, is the topic of dietary fat, which has become “more rather than less murky in the recent past,” she said.

Lichtenstein explained that early guidance for the prevention and treatment of cardiovascular disease from the early 1960’s suggested replacing food sources of saturated fat —red meat, butter, cheese, etc.— with unsaturated fat —olive oil, avocados, most nuts and seeds, etc.

Sometime after that, she said, the emphasis shifted to reduce total fat. Looking retrospectively, however, this shift resulted in an increase in (mostly refined) carbohydrate intake. Accompanying dyslipidemia (or the abnormal amount of lipids in the blood) moved the pendulum back to a renewed emphasis on fat substitution, which according to her, didn’t quite settle the issue either.

Not All Fats Are Created Equal

“Critical but sometimes lost…is distinguishing among the replacement macronutrients,” said Lichtenstein. In other words, it is not only important to replace animal fat but to choose your replacements wisely, she explained.

“In the last few years, for instance, headlines in major outlets have been touting the benefits of butter as a better option than other spread replacements containing trans fats,” she said. “While this is true, what people usually overlook is that butter is still saturated fat, which increases blood cholesterol levels and the risk of heart disease.” Switching to natural sources of unsaturated fats, she suggested, is much better.

Lichtenstein also made a special mention of coconut oil, which in recent times has been consistently advertised as a dietary panacea. Conceding that coconut oil consumption skyrocketed as media hammered its alleged benefits compared to butter and other animal fat replacements, she emphasized the importance of “reading the small print.” “Coconut oil is vegetable fat, which is better than animal fat,” she explained. “But it still contains high levels of saturated fat, which have proved to be detrimental to human health.”

Public opinion is catching up, she announced. Last year, according to Lichtenstein, coconut oil sales plummeted. It seems more people are grasping a better understanding of the differences between various types of fats and their effect on human health, she said.

“Currently, the predominance of data supports the recommendation to replace foods high in saturated fat with those high in unsaturated fat,” she concluded.

The Role of Media Ethics

Lichtenstein’s plenary presentation also included a candid assessment of what she thinks is a key component of nutrition advice information or disinformation—media ethics. She shared how, in a private conversation, a friend working in media confessed to her how the pressure of increasing the number of visits and clicks on posted stories is bearing down on many working in the field.

It is something, Lichtenstein said, that is pushing some reporters past ethical concerns to look for ‘shocking’ health headlines and commentaries, which may not always be accurate.

“At the end of the day, it all boils down to the ethics of individual reporters,” she said, “and there is not much we can do about it.”

It is another reason, she concluded, why a critical perusal of stories shared in the media is essential. “In sifting through conflicting or contradictory evidence, the more elements we consider, the better decisions we will likely make,” she said.

Marcos Paseggi, Adventist Review