[Fan Zhihong Registered Dietitian Original Content Welcome to Forward]
Recently, someone asked, I heard that the latest research found that eating more apples and bananas every day can prolong the life of people with high blood pressure?
Yes, there are results. To be more rigorous, nutritional epidemiological studies have found that eating apples and bananas on a daily basis is associated with a lower risk of all-cause mortality in people with high blood pressure.
Reducing the risk of all-cause mortality means that the likelihood of dying from a variety of diseases is reduced, except for accidents. In other words: it is to live longer and prolong life.
The new study found that people with high blood pressure who regularly ate apples and bananas had significantly lower all-cause mortality than those who didn't.
Statistics show that patients with high blood pressure who eat 3~6 apples a week have a 40% lower all-cause mortality rate than those who eat less than one apple a month. Patients with high blood pressure who ate 3~6 bananas per week had a 24% lower all-cause mortality rate than those who ate less than one banana per week. Those who ate 3~6 apples or bananas per week had a 43% reduction in all-cause mortality compared to those who ate less than once in a month [1].
What about other fruits? No significant effect was observed. Only apples and bananas stand out.
Why are fruits cardiovascularly friendly?
In fact, not only apples, but also fruits are good for blood pressure control, which is not new news. A number of studies at home and abroad have confirmed that eating fruits in moderation every day is beneficial to the prevention and control of hypertension and the risk of cardiovascular and cerebrovascular diseases [2]. Therefore, the dietary guidelines for Chinese residents recommend that adults eat 200~350 grams of fruits per day.
Someone asked: I don't eat fruits, only vegetables, can't I?
When it comes to cardiovascular health, fruits and vegetables have their own unique advantages.
Because, to prevent and control high blood pressure, a diet high in potassium and low in sodium is required. The main sources of sodium are salt and savory condiments, and meat also contains some sodium. The sources of potassium are vegetables, fruits, legumes, whole grains, meat, dairy, and many other foods, among which vegetables and fruits are particularly important.
Fruits are a dietary source of potassium, but they are very low in sodium. In contrast, although vegetables are also rich in potassium, eating vegetables usually requires cooking, and salt is used in cooking, which greatly increases the sodium content.
Eating fruit is usually eaten directly, or juiced to eat, and there is a high probability that there is no need to put salt. Therefore, fruits only supplement potassium and do not supplement sodium, so it can well change the ratio of potassium and sodium in the diet, which is especially beneficial for hypertensive patients who need a high-potassium and low-sodium diet.
At the same time, fruits do contain a large number of flavonoids that reduce inflammation and protect cardiovascular health, as well as vitamin C.
(The key is to eat in moderation every day, not sometimes crazy to eat in large quantities and sometimes not for a long time...... ）
Therefore, eating vegetables is not a complete substitute for eating fruits, unless you drink some extra vegetable juice without salt or sugar.
Apples are also blood sugar friendly?
Eating apples is not only good for blood pressure control, but also very good for blood sugar control. Epidemiological studies have found that people who eat apples have a lower risk of diabetes [3].
In vitro assays have found that apples can effectively reduce the activity of α-amylase and glucosidase [4].
In other words, although apples themselves contain sugar, which will cause a rise in blood sugar, eating apples with starchy foods is conducive to delaying the digestion and absorption of starchy foods. So, as a result of both effects, theoretically, apples and rice when eaten together do not cause an additional rise in blood sugar levels.
In fact, blood glucose experiments have also shown that if apples are used to replace a small portion of rice with a small amount of carbohydrates, then when apples and rice are eaten together, the postprandial blood sugar response is slightly lower [5]. Fruit and rice/steamed buns are mixed and eaten, the taste is actually very good, and there will be no uncomfortable feeling, and it will not feel particularly "cold", which is suitable for the elderly and infirm.
The blood sugar test we did also proved that eating a small apple (160 grams) about half an hour before a meal was effective in reducing blood sugar fluctuations after a meal. Whether you replace two bites of rice or eat extra apples, the peak blood sugar after a meal is lower compared to eating rice alone [6].
Do apples still have health effects when cooked?
When it comes to apples, many friends say: I can't eat fresh apples. Some people also say: when you eat an apple, your stomach is uncomfortable.
If you eat baked apples, steamed apples, boiled apples, dried apples, can you still get these health benefits?
The answer is: yes, still good.
Many people say that fresh fruits are relatively "cold", and eating them is prone to intestinal sound, diarrhea, and unformed poop. In other words, the effect of fresh apples in promoting intestinal motility is too strong. However, this shortcoming can be remedied.
Just by heating the apples, the elderly and those with indigestion can feel much more comfortable. Therefore, apples are often added to the "health drinks" circulating everywhere on the Internet, and apple powder is often added to various "grain health powders". It can be seen that heated apples are still relatively friendly to digestion and suitable for frail people.
The potassium and dietary fiber in apples are not lost due to heating and are heat-stabilized ingredients. The content of polyphenols in it can even increase slightly under the condition of boiling for a short period of time after boiling for a few minutes. This is because a part of the polyphenols are bound to the cell wall, and during the heating process, the complete structure of the cell wall is destroyed, and the polyphenols in it are released. The pectin in the peel will also gradually dissolve and be more easily used by the body.
The sugar in apples is also not destroyed by heating. It is even possible that small amounts of new oligosaccharides can be formed as a result of heating, which are "prebiotic" components that benefit gut health.
It is vitamin C that is really more afraid of heat, and it just so happens that the vitamin C content of apples is very low, only a fraction or even one-tenth of vegetables such as cabbage, potatoes, and radishes, even if they are all lost, there is no need to be a pity.
Therefore, whether it is boiled, steamed, or baked, there is not much loss in nutrition. What I advocate the most is baked apples, which are a wonderful aroma and soft texture, which is a real pleasure.
Unpublished data done in our lab shows that apples heated in the microwave are still friendly to postprandial blood sugar.
In addition, we found that dried apples are also a good thing, as they have the lowest glycemic index (GI) of all dried fruits. Eating dried apples with 15 grams of sugar half an hour before a meal, followed by rice, can reduce the glycemic response of a rice meal [7].
Why are apples so good for health?
In fact, there are so many nutritional studies on the health benefits of eating apples, and they are not limited to prolonging the life expectancy of people with high blood pressure.
For example, eating apples is beneficial in preventing cancers of the mouth, esophagus, and stomach [8]; Eating apples is beneficial to control blood cholesterol levels and prevent cardiovascular and cerebrovascular diseases [9]; Apple extract is good for bone health, good for reducing inflammation in blood vessels, and so on.
In the case of the new study, the researchers believe that bananas are particularly high in potassium, while apples are not too high in potassium but high in flavonoids, so they are particularly friendly to people with high blood pressure.
However, I think there are some important reasons for this: apples and bananas are two fruits that are consumed in large quantities, are inexpensive, available in all seasons, have an acceptable taste, and are consumed in large and stable quantities.
Even if some fruits are more nutritious, if the supply season is limited and therefore cannot be consumed all year round, if the price is high and many people cannot afford it, if the amount eaten at one time is too small, then it is difficult to show such obvious health effects in epidemiological studies.
For example:
- Although strawberries, kiwifruit, persimmons, and other fruits are also rich in potassium, they are not eaten 365 days a day.
- Although the flavonoid content of fruits such as hawthorn and begonia is significantly higher than that of apples, their consumption is too low, and the total amount eaten is very small on an annual basis.
- Tropical fruits such as mango, mangosteen and pineapple are consumed in smaller quantities in non-tropical areas. (This study analyzed data from the United States Nutritional Diet Survey.) ）
- Blueberries, cranberries, and blue indigo nuts are not only expensive, but also relatively small in quantities. In comparison, if you eat one apple or one banana, you will have 100 to 200 grams.
Therefore, the health effect of a food depends not only on its own nutritional and health care ingredients, but also on its consumption and frequency. Just like a toxic substance, how toxic it is, not only depends on its own semi-lethal amount data (toxicity), but also at the bottom of how much (dose) it has eaten at one time and how many times it has been eaten (exposure frequency).
Related Literature:
1 Sun C, Li J, Chen L, et al. The correlation between fruit intake and all-cause mortality in hypertensive patients: a 10-year follow-up study. Erontiers in Nutrition, 2024, 11:1363574.
2 Du H , Li L , Bennett D , et al. Fresh fruit consumption and major cardiovascular disease in China. New England Journal of Medicine, 2016, 375(5):489-489.
3 Guo X, Yang B, Tang J, et al. Apple and pear consumption and type 2 diabetes mellitus risk: A meta-analysis of prospective cohort studies. Food and Function. 2017, 8, 927–934.
4 Wang C, Zhang Chixiang, Pu Bo, et al. Inhibitory Activity of 45 Vegetables and Fruits on α-Glucosidase and α-Amylase, Food Science and Technology, 2015, 40(03):20-22
5 Lu J, Zhao W, Wang L, et al. Apple Preload Halved the Postprandial Glycaemic Response of Rice Meal in Healthy Subjects[J]. Nutrients, 2019, 11:2912.
6 Lu X, Lu J, Fan Z, et al. Both Isocarbohydrate and Hypercarbohydrate Fruit Preloads Curbed Postprandial Glycemic Excursion in Healthy Subjects. Nutrients, 2021, 13. 2470.
7 Zhao W, Wang L, Fan Z, et al. Co-ingested vinegar-soaked or preloaded dried apple mitigated acute postprandial glycemia of rice meal in healthy subjects under equicarbohydrate conditions. Nutrition Research, 2020, 9:108-118
8 Sandoval-Ramirez BA, Catalan U, Calderon-Perez L, et al. The effects and associations of whole-apple intake on diverse cardiovascular risk factors. A narrative review. Critical Reviews in Food Science and Nutrition, 2020, 60(22):835-843.
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Fan Zhihong
He is a scientist at the Beijing Advanced Innovation Center for Food Nutrition and Human Health
Director of the Chinese Nutrition Society
Director of China Health Promotion and Health Education Association
The China Association for Science and Technology has hired the chief expert of nutrition science communication
Ph.D. in Food Science, China Agricultural University