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Washington D.C., Apr 4: While consuming a high-diet salt can result in high blood pressure, a recent study has revealed a link between salt-rich diet and weaker immune system.

The study was conducted under the leadership of the University Hospital Bonn, and the results were published in the journal Science Translational Medicine.

The research was conducted on mice that were fed a high-salt diet. Later, they were found to suffer from much more severe bacterial infections.

Human volunteers who consumed an additional six grams of salt per day also showed pronounced immune deficiencies.

The World Health Organization (WHO) has recommended a maximum amount of five grams of salt a day.

It corresponds approximately to one level teaspoon. In reality, however, many Germans exceed this limit considerably. 

Figures from the Robert Koch Institute suggest that on average men consume ten, and women more than eight grams a day.

This means that we reach for the salt shaker much more than is good for us. After all, sodium chloride, which is its chemical name, raises blood pressure and thereby increases the risk of heart attack or stroke.

"We have now been able to prove for the first time that excessive salt intake also significantly weakens an important arm of the immune system," said Prof. Dr. Christian Kurts from the Institute of Experimental Immunology at the University of Bonn.

This finding is unexpected, as some studies point in the opposite direction. For example, infections with certain skin parasites in laboratory animals heal significantly faster if these consume a high-salt diet.

The study also sheds light on the fact that the skin serves as a salt reservoir.

"Our results show that this generalization is not accurate," emphasized Katarzyna Jobin, lead author of the study.

The body keeps the salt concentration in the blood and in the various organs largely constant. Otherwise important biological processes would be impaired. The only major exception is the skin which functions as a salt reservoir of the body. This is why the additional intake of sodium chloride works so well for some skin diseases.

However, other parts of the body are not exposed to the additional salt consumed with food. Instead, it is filtered out by the kidneys and excreted in the urine.

"We examined volunteers who consumed six grams of salt in addition to their daily intake," said Prof. Kurts. This is roughly the amount contained in two fast-food meals, i.e. two burgers and two portions of French fries.

After one week, from the results, it showed that the immune cells coped much worse with bacteria after the test subjects had started to eat a high-salt diet.

In human volunteers, excessive salt intake also resulted in increased glucocorticoid levels.

Europe, Jan 11: Researchers have revealed the people who drink tea at least three times a week have healthy years of life and longer life expectancy.

The research was published in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).

Dr Xinyan Wang, who is the author of the study, said: "Habitual tea consumption is associated with lower risks of cardiovascular disease and all-cause death. The favourable health effects are the most robust for green tea and for long-term habitual tea drinkers."
The analysis that was conducted included about 100,902 participants of the China-PAR project2 with no history of heart attack, stroke, or cancer.

Participants were classified into two groups: Habitual tea drinkers and never or non-habitual tea drinkers and followed-up for a median of 7.3 years.

The analyses estimated that 50-year-old habitual tea drinkers would develop coronary heart disease and stroke 1.41 years later and live 1.26 years longer than those who never or seldom drank tea. Compared with never or non-habitual tea drinkers, the habitual tea consumers had a 20 per cent lower risk of incident heart disease and stroke, 22 per cent lower risk of fatal heart disease and stroke, and 15 per cent decreased risk of all-cause death.

The potential influence of changes in tea drinking behaviour was suspected in a subset of 14,081 participants with assessments at two-time points. The average duration between the two surveys was 8.2 years, and the median follow-up after the second survey was 5.3 years.

Habitual tea drinkers who maintained their habit in both surveys had a 39 per cent lower risk of incident heart disease and stroke, 56 per cent lower risk of fatal heart disease and stroke, and 29 per cent decreased risk of all-cause death compared to consistent never or non-habitual tea drinkers.

Senior author Dr Dongfeng Gu said: "The protective effects of tea were most pronounced among the consistent habitual tea drinking group. Mechanism studies have suggested that the main bioactive compounds in tea, namely polyphenols, are not stored in the body long-term. Thus, frequent tea intake over an extended period may be necessary for the cardioprotective effect."

In a subanalysis by type of tea, drinking green tea was linked with approximately 25 per cent lower risks for incident heart disease and stroke, fatal heart disease and stroke, and all-cause death. However, no significant associations were observed for black tea.
Dr Gu noted that a preference for green tea is unique to East Asia.

Two factors may be at play. First, green tea is a rich source of polyphenols which protect against cardiovascular disease and its risk factors including high blood pressure and dyslipidaemia. Black tea is fully fermented and during this process, polyphenols are oxidised into pigments and may lose their antioxidant effects. Second, black tea is often served with milk, which previous research has shown may counteract the favourable health effects of tea on vascular function.

Gender-specific analyses showed that the protective effects of habitual tea consumption were pronounced and robust across different outcomes for men, but only modest for women. Dr Wang said: "One reason might be that 48 per cent of men were habitual tea consumers compared to just 20 per cent of women. Secondly, women had a much lower incidence of, and mortality from, heart disease and stroke. These differences made it more likely to find statistically significant results among men."

She said: "The China-PAR project is ongoing, and with more person-years of follow-up among women the associations may become more pronounced."

In conclusion, the authors have found that randomised trials are required to validate the results and to illustrate nutritional guidelines and advice for lifestyle.

The World Health Organisation has warned that the COVID-19 pandemic is entering a "new and dangerous" phase. Thursday saw the most cases in a single day reported to the WHO.

Tedros Adhanom Ghebreyesus said the day had seen 150,000 new cases with half of those coming from the Americas and large numbers also from the Middle East and South Asia, the BBC reported.

He said the virus was still spreading fast and the pandemic accelerating.

He acknowledged people might be fed up with self-isolating and countries were eager to open their economies but he said that now was a time for extreme vigilance.

Maria van Kerkhove, technical lead of the WHO's COVID-19 response, told a press conference the pandemic is "accelerating in many parts of the world".

"While we have seen countries have some success in suppressing transmission and bringing transition down to a low level, every country must remain ready," she said.

Mike Ryan, the head of the WHO's Health Emergencies Programme, said that some countries had managed to flatten the peak of infections without bringing them down to a very low level.

"You can see a situation in some countries where they could get a second peak now, because the disease has not been brought under control," he said.

"The disease will then go away and reduce to a low level, and they could then get a second wave again in the autumn or later in the year."