Don't equate fat with disease

"Eating fat will block blood vessels
.
"

"Eating too much meat leads to swimming rings
on my stomach.
"

For a long time, the public has stereotyped that every chronic disease is more or less related
to fat.
In fact, as one of the three major nutrients in humans, a proportional intake of different types of fat can take care of health
.
Recently, the "6th International Symposium on Lipid Science and Health 2022", jointly organized by the Institute of Oil Crops of the Chinese Academy of Agricultural Sciences and Northwest A&F University, focused on cutting-edge academic topics such as lipid science and health
.

The rising prevalence of chronic diseases is a cause for concern

The Lancet published a study showing that after tracking the dietary structure and habit trends of adults aged 25 and over in 195 countries from 1990 to 2017, 11 million people died from eating unhealthy in 2017, accounting for 22%
of the total adult deaths.

Jiang Yuanrong, general manager of Wilmar (Shanghai) Biotechnology R&D Center, introduced that unhealthy diet is one of the risk factors for the onset of
diabetes.
Data show that the prevalence of diabetes in China is still rising, reaching 11.
2%
from 2015 to 2017.
At the same time, hyperlipidemia is one of the main risk factors for cardiovascular disease, and the primary dietary factors that increase blood cholesterol are: high-cholesterol food intake, high-saturated fatty acid food intake and excessive
calorie intake.

The rise in the incidence of chronic diseases worldwide has attracted the attention of the public to chronic diseases
.
"It is widely believed that every chronic disease is more or less associated
with fat.
" Yu Weizu, president of the Good Food Nutrition and Health Research Institute of Good Shop Co.
, Ltd.
, said that JAMA Internal Medicine (JAMA Internal Medicine) included a paper by researchers at the University of California, San Francisco in 2016, which pointed out that in the 60s of the 20th century, saturated fat was known as the culprit of cardiovascular disease, shaping the concept
that "the source of many diseases is fat".

In 1955, former U.
S.
President Dwight Dwight D.
Dwight D.
D.
Eisenhower had a heart attack, bringing public attention to heart disease to a climax
.
The incidence of heart disease in the United States rose at a visible rate in the early 20th century, and by the 50s of the 20th century, heart disease had become the number one killer of health, when scientists around the world were scrambling to figure out what caused the explosion of cardiovascular disease
.

University of Minnesota professor Ancel Keys famously proposed the "fat hypothesis" in 1958 — fat is responsible for heart disease
.
He then conducted a large study spanning seven countries in Italy, Greece, Yugoslavia, Finland, the Netherlands, Japan, and the United States, the Seven Nations Study (1958-1964), investigating the relationship between fat intake and heart disease incidence
.
The results of the survey showed that saturated fat intake was positively correlated with the incidence of heart disease in seven countries, as
hypothetically.

In 1980, the U.
S.
government introduced the first dietary guidelines in U.
S.
history, advising the public to avoid saturated fat
.
"So people began to change their dietary patterns to low-fat and high-carbs, but the relative reduction in fat intake led to a large intake of sugar and refined carbs, and the structure of oil intake also changed; After the advent of hydrogenated oils, it caused the intake
of trans fatty acids.
The data shows that the obesity rate is increasing year by year, and the incidence of heart disease, diabetes and other diseases is also increasing
.
In fact, Keith's research began as a "22-country study", because only 7 country survey results matched his hypothesis, so the results of the other 15 countries were deleted by him
.

Scientists have lived with Inuit in the Arctic archipelago for months, studying their diets
.
Living in the Arctic, limited by the geographical environment, Inuit can only eat meat and animal fats most of the time, such as birds, reindeer, seals, walruses, whales, etc.
, and in the summer, they are likely to eat some plant foods, such as berries, roots, etc
.
The results of the study showed that Inuit had a lower
incidence of cardiovascular and cerebrovascular diseases while consuming more fat.

Fat is also divided into "three, six, nine, etc.
"

With the deepening of fat research, more and more studies prove that fat is not all "bad", and the type of dietary fat is more important
.

A study in BMC Medicine explored the relationship
between six commonly used cooking oils and cardiac and all-cause mortality.
The study selected 520,000 participants aged 50-71 years from the National Institutes of Health (AARP) for follow-up studies, recorded and calculated the total intake of edible oil in various foods through a food frequency questionnaire (FFQ), and counted the types of edible oils used in cooking (butter, margarine, lard, corn oil, canola oil, and olive oil), dosage and frequency, and regularly followed
up the participants' physical condition.

With a follow-up of up to 16 years, the team recorded a total of 129328 deaths
.
Studies have found that butter and margarine intake are associated with higher all-cause mortality, while low canola and olive oil intake is associated with
lower all-cause mortality.
Consuming an additional 1 tablespoon of butter or margarine per day increased all-cause mortality by 7% and 4%, respectively; Conversely, consuming an extra tablespoon of canola or olive oil per day reduced mortality by 2% and 3%.

In addition, the study also found that eating butter was positively correlated with cancer mortality, which increased the risk
of death in cancer patients.
Conversely, replacing equal amounts of butter and margarine with corn oil, canola oil or olive oil reduces mortality from certain causes, including cancer, cardiovascular disease, diabetes, respiratory diseases and Alzheimer's disease
.

The new version of the dietary guidelines for Chinese residents mentioned evidence on fat and health, Jiang Yuanrong introduced that according to evidence-based medical methods, high fat intake can increase the risk of obesity, reducing total fat intake can help reduce weight, evidence credibility level A; Partial substitution of polyunsaturated fatty acids for saturated fatty acid intake may reduce the risk of coronary heart disease, confidence level B; Excessive intake of trans fats increases the risk of death from cardiovascular disease, confidence level B
.

Liu Yuanfa, Dean of the School of Food Science of Jiangnan University, introduced that by simulating the typical oil digestion rate and digestibility characteristics of gastrointestinal digestion, the research team found that palm oil and rapeseed oil had a high degree of hydrolysis, flaxseed oil and sunflower oil had a slower hydrolysis rate, lard had a slow hydrolysis rate and the lowest
total hydrolysis degree.
Then, the absorption characteristics of different oils were analyzed by characterizing the composition and changes of serum fatty acids after meals.
By analyzing the lipid composition of fat and liver and the expression of genes related to metabolism, the effects of
different lipid intake on lipid homeostasis regulation in the body were analyzed.

Liu Yuanfa's team came to the following conclusions: palm oil is mainly saturated fatty acid, with the highest digestion rate and digestibility, and long-term intake can cause elevated blood lipids TG, TC, LDL-C, INTESTINAL BARRIER DISORDER, AND INTESTINAL INFLAMMATION; Lard is mainly saturated fatty acid, the degree of digestion and digestion rate are low, long-term intake can cause intestinal barrier disorder, intestinal inflammation, liver lipid deposition, elevated blood lipids TG, TC, LDL-C; Canola oil is mainly an unsaturated fatty acid, with high digestion degree and digestion rate, long-term intake can reduce LDL-C ratio and protect the intestinal barrier; Sunflower oil is mainly unsaturated fatty acids, with fast digestion rate and low degree of digestion, and long-term intake can reduce the proportion of LDL-C; Flaxseed oil is mainly an unsaturated fatty acid, with a low digestion rate and a high degree of final digestion, and long-term intake can reduce the LDL-C ratio and protect the intestinal barrier
.

The World Health Organization recommends that N-6 unsaturated fatty acids and N-3 unsaturated fatty acids be consumed in a ratio of 4:1 to 6:1, which can improve cardiovascular health
.

(Wang Jiayi, Liu Yanfang)

China Food News(November 30, 2022, Version 03)

(Responsible editor: Han Songyan).