Eating "cold rice" regularly can lower blood lipids, blood sugar, and even improve fatty liver?

Rice is an indispensable staple food on the table. Most people eat it while it is hot. However, some people prefer to eat cold rice because they heard that eating cold rice can lower blood lipids and blood sugar, and even help recover from fatty liver. Is this really the case? Does eating cold rice have so many benefits?

Let me start with the conclusion: the reason why some people's blood lipids and blood sugar levels drop after eating cold rice is actually because of the resistant starch in the cold rice. However, resistant starch is an ingredient found in many foods, and eating more other foods rich in resistant starch is also fine. It is not necessary to eat cold rice. Because cold rice is not delicious, and it is not friendly to people with poor gastrointestinal function.

What's special about cold rice

Under normal circumstances, the starch structure contained in rice is amylose. During the process of steaming and cooking rice, amylose will absorb water, swell and gelatinize. At this time, the starch in the rice is fast-digesting starch, and amylase can freely break them down into glucose for use by the human body.

However, if the cooked hot rice is placed in the refrigerator and becomes cold rice, then the "aging and regeneration" phenomenon will occur at low temperatures. At this time, the resistant starch content in the rice will increase. An experiment has shown that after the cooked ordinary japonica rice is placed in the refrigerator for 24 hours, the resistant starch content increases from 4% to 14%, an increase of 10%.

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Some people may ask: "What exactly is resistant starch?" To understand it, you must first understand the classification of starch. According to the degree of digestion, the starch in food can be divided into three categories, including fast-digesting starch, slow-digesting starch, and resistant starch.

1. Fast digesting starch

It is absorbed quickly in the small intestine and can be digested and absorbed within 20 minutes. It not only provides energy quickly, but also causes blood sugar levels to rise rapidly.

2. Slowly digested starch

It is absorbed slowly in the small intestine and generally takes 20 to 120 minutes to be digested and absorbed. It can provide energy continuously and keeps blood sugar levels rising more steadily.

3. Resistant Starch

It cannot be digested and absorbed in the small intestine, nor can it be broken down into glucose for use by the human body. It produces almost no energy and does not increase blood sugar.

However, it should be noted that cold rice is not suitable for everyone. Usually, eating warm food will make us feel very comfortable in the stomach, while eating cold food will often make people feel gastrointestinal discomfort.

Therefore, people with poor digestion, gastrointestinal discomfort, and frequent flatulence should not try it, so as not to aggravate the condition and lose more than the gain. This is especially true for children, the elderly, pregnant women and other people who are in the process of growth and development.

Another reminder: If you want to eat cold rice, you must pay attention to the environment in which the rice is stored, seal it well and refrigerate it, and don't store it for too long. Cold food is easily targeted by bacteria. If it is infected with pathogenic bacteria such as Listeria, Salmonella, Escherichia coli, Bacillus cereus, etc., be careful that it may cause food poisoning!

Resistant starch has many benefits

The increase in resistant starch content is a major feature of cold rice, which is why it is favored by many people. Eating foods rich in resistant starch regularly is good for human health and does have many positive effects.

1. Protect the Liver

Researchers from Shanghai Sixth People's Hospital and the Hans Knoll Institute in Germany collaborated to publish a study in the journal Cell Metabolism. A total of 200 volunteers with fatty liver were recruited, including 145 males and 55 females with an average age of 39.1±9.1 years. The volunteers were randomly divided into two groups, receiving resistant starch intervention and an equal amount of control starch intervention respectively.

Among them, volunteers in the resistant starch group ate 40g of resistant starch extracted from corn every day, while the control group ate non-resistant starch with the same calories. After 4 months, it was found that the triglyceride content in the liver of the volunteers in the control group dropped from 23.51% to 21.44%, while the triglyceride content in the liver of the volunteers in the resistant starch group dropped from 24.99% to 13.14%, with a significant effect, and the liver function indicators of the volunteers in the resistant starch group were improved.

2. Improve blood lipid levels

The study by Shanghai Sixth People's Hospital and Germany's Hans Knoll Institute also found that the volunteers in the resistant starch group had improvements in total cholesterol, triglycerides, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol.

Other studies have shown that when patients with metabolic syndrome consumed foods containing resistant starch (whole grains) for 12 weeks, their plasma triglyceride levels decreased by 43%.

3. Lose weight and control weight

Obesity is closely related to excessive calorie intake, and reducing calorie intake can help lose weight. Foods rich in resistant starch can enhance satiety, reduce appetite, and reduce calorie intake, thereby helping to lose weight and control weight.

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Research conducted by Shanghai Sixth People's Hospital and Germany's Hans Knoll Institute also mentioned the role of resistant starch foods in weight control. In the study, the weight, waist circumference, BMI, body fat percentage and other indicators of the volunteers in the resistant starch group were significantly reduced.

4. Prevents Colon Disease

Resistant starch is also a kind of dietary fiber. Although it cannot be absorbed and utilized in the small intestine, it can reach the colon after 2 hours and be fermented by the microbial flora in the colon. It helps to increase the level of short-chain fatty acids, lower intestinal pH, inhibit the growth and reproduction of pathogenic bacteria, and promote the growth of intestinal probiotics, which is beneficial for preventing colon diseases.

5. Improves Blood Sugar Levels

Adding foods rich in resistant starch to the diet can help lower the GI value and stabilize blood sugar after meals. Foods rich in resistant starch can also increase insulin sensitivity and improve insulin resistance, which in turn helps stabilize blood sugar and prevent the occurrence of type 2 diabetes.

6. Promote the absorption and utilization of minerals

Studies have mentioned that resistant starch can improve the absorption and utilization rate of minerals such as magnesium ions, calcium ions, iron ions, and zinc ions in the human ileum. The short-chain fatty acids produced by the fermentation of resistant starch in the large intestine can also promote the absorption and utilization of minerals.

Seeing this, some people may ask, since resistant starch has so many benefits, will the resistant starch content of all staple foods increase after being cooled?

The answer is: No. This method only has a significant effect on foods with high content of amylose, such as rice, steamed bread, and bread, but has little effect on foods with high content of amylopectin, such as glutinous rice balls, Yuanxiao, and zongzi.

Which foods contain resistant starch?

So besides cold rice, what other foods can we use to get resistant starch? In fact, there are quite a lot of foods rich in resistant starch.

① Unripe green bananas are a relatively rich source of resistant starch, with a content of up to 51.3%, while the resistant starch content of ripe yellow bananas is 15.8%.

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②The resistant starch content of potatoes is 50%~66%, and the resistant starch content of potato starch is 57%~76%.

③Buckwheat flour contains a higher proportion of resistant starch, with a content of 33.5%.

④The resistant starch content of peas is 32.6%.

⑤ The resistant starch content of chestnuts is also good. The resistant starch content in raw chestnuts is 27.44%, accounting for 68.93% of the total starch; the resistant starch content in cooked chestnuts is 5.46%, accounting for 13.69% of the total starch, and the resistant starch content in cooked chestnuts shows an upward trend within 24 hours of refrigeration.

⑥ Foods with low water content and low processing temperature, such as noodles and biscuits, have relatively high resistant starch content; puffed foods, bread products and porridge drinks contain almost no resistant starch or the content is very low.

Summarize:

Resistant starch has many health benefits. It can help us stabilize blood sugar, lose weight, protect liver and blood lipids, and promote intestinal health. Even so, don't force yourself to eat cold rice just to get resistant starch! You can increase the intake of buckwheat flour, potatoes, peas, green bananas, beans, nuts and other foods appropriately, which can help us take in more resistant starch.

References

[1] Wang Lu, Fan Zhihong, Shi Haiyan, et al. Starch digestibility of several glutinous foods[J]. Food Science, 2010, 31(17): 359-363.

[2] Zhu Ping, Kong Xiangli, Bao Jinsong, et al. Research progress on the application and efficacy of resistant starch in food[J]. Journal of Nuclear Agricultural Sciences, 2015, 29(2): 327-336. DOI: 10.11869/j.issn.100-8551.2015.02.0327.

[3]Ni, Yueqiongetal. "ResistantstarchdecreasesintrahepatictriglyceridesinpatientswithNAFLDviagutmicrobiomealterations." Cellmetabolismvol.35,9(2023):1530-1547.e8.doi:10.1016/j.cmet.2023.08.002

[5] Zhou Yu, Tong Guanqun, Yang Ke, Yan Yao, Zhang Yukun, Liu Wenmeng, Chen Long. Research progress on the application of resistant starch in elderly food[J]. Journal of Cereals, Oils and Food Science and Technology, 2023, 31(6): 43-50

[4] Zhu Ping, Kong Xiangli, Bao Jinsong. Research progress on the application and efficacy of resistant starch in food[J]. Journal of Nuclear Agricultural Sciences, 2015, 29(2): 327-336

[6] Wang Zhu, Li Jianwen, Yang Xiaoli, Yang Jingming, Yang Yuexin. Analysis of resistant starch content in food[J]. Journal of the Chinese Cereals and Oils Association, 2007, 22(6): 82-85108

[7] Zhang Huiyu. Research on factors affecting buckwheat noodle quality and establishment and verification of prediction model[D]. Jiangnan University, 2023. DOI: 10.27169/d.cnki.gwqgu.2023.000520.

[8] Qin Haibing, Mo Kaiju, Wang Xingping. Types of carbohydrates in chestnut and their digestibility[J]. Food Science, 2010, 31(21): 191-194

Author: Xue Qingxin, registered nutritionist

Review丨Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center