Vegetarians more susceptible to depression than meat eaters, study shows. Here’s why

Vitamin and mineral deficiencies in vegetarian diet bad for mental health, study shows. Also in the news: smoking primes lung cells to develop cancer; mums-to-be who drink alcohol now and then may be doing no harm

PUBLISHED : Wednesday, 13 September, 2017, 12:48pm
UPDATED : Wednesday, 13 September, 2017, 12:48pm

Vegetarians are at higher risk of suffering depression compared to those who eat meat and follow a conventional balanced diet, according to a new study.

A Bristol University study of almost 10,000 people from southwest England discovered that vegetarians were almost twice as likely to develop depression because of vitamin and mineral deficiencies that can negatively affect their mental health.

The 350 committed vegetarians who took part in the study had a higher average depression score compared to the meat eaters, according to the study published in the Journal of Affective Disorders.

Roughly 50 per cent of vegans and 7 per cent of vegetarians have a vitamin B12 deficiency. Vitamin B12 can be found in red meat seafood and plays an important role in affecting an individual’s mood.

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Vegans and vegetarians also have a greater intake of nuts that contain omega-6 fatty acids, which have been linked with an increased risk of mental health problems.

“Other potential factors include high blood levels of phytoestrogens (oestrogen that’s naturally in legumes) – consequent mainly on diets rich in vegetables and soya,” the report stated. “Another potential contributing factor is that lower intakes of seafood are thought to be associated with greater risk of depressive symptoms.”

The lack of a balanced diet can influence the development of depression.

Research findings also can be attributed partially to iron deficiencies, the study says.

Participants who had been consuming a vegetarian diet for longer periods of time had higher depression scores throughout.

The study, however, did not rule out the possibility that the vegetarians’ decisions to adopt their diet could have been a symptom of depression from the get-go. TNS

Smoking sets the lungs up for cancer

Chronic exposure to cigarette smoke can change lung cells over time, making them more vulnerable to disease and priming them to develop cancer, say US researchers.

The report in the journal Cancer Cell is based on lab experiments on lung cells that were exposed to chronic cigarette smoke – the equivalent of a person smoking for 20 to 30 years.

After about 10 days, the cells began to change their gene expression, a process known as epigenetic change.

It took 10 months before these changes built up enough to boost the odds of cancer.

“When you smoke, you are building up a substrate of epigenetic changes that we hypothesise are increasing your odds for developing lung cancer,” says senior author Stephen Baylin, co-director of the Cancer Biology programme at Johns Hopkins University.

“Because if you’re not a smoker, your risk of lung cancer is very low.”

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These epigenetic abnormalities essentially turn off multiple genes which are needed to help protect normal cells from developing cancer.

Epigenetic changes do not alter, or mutate, the basic DNA sequence of the gene, suggesting that there is hope for people who want to quit smoking.

“This work suggests the possibility that unlike mutations, which are harder to reverse, if you stop smoking at a certain time and duration, then you have a chance to decrease the chance that might be due to the build-up of epigenetic changes,” says first author Michelle Vaz, a postdoctoral researcher at Johns Hopkins University School of Medicine.

“The hypothesis is that there are potentially reversible changes that are contributing to a certain set of lung cancers.”

In Hong Kong, lung cancer has been the leading cause of cancer death for many years, claiming 4,031 lives in 2015. AFP

Lack of information on pregnancy and drinking

How much alcohol is it safe for a pregnant woman to drink?

For a question that affects so many people, surprisingly little research has been done, say health experts who reviewed the scant evidence and published in BMJ Open.

While there is widespread awareness of fetal alcohol syndrome, which can cause brain damage in unborn babies whose mothers drink, nobody knows how much it takes, or whether there is a safe limit for pregnant women to enjoy an occasional tipple.

A trawl for research on the topic found “a surprisingly limited number” of studies into low alcohol consumption during pregnancy.

And given the “paucity of evidence”, the advice for now must remain “better safe than sorry,” the researchers conclude.

The team searched far and wide for data on pregnant women who had imbibed four units per week – a total of 32 grams or 40ml of pure alcohol – considered in Britain as “light” consumption.

A unit in Britain is about half a pint (284ml) of beer, half a glass of wine, or half a shot of the hard stuff.

The recommended British limit for adults is 14 units, but for pregnant women, the advice is complete abstinence.

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Guidelines differ between countries, but the issue is controversial.

According to the authors, up to 80 per cent of mothers-to-be in Britain, Ireland, New Zealand and Australia drink some alcohol while pregnant.

A study earlier this year in 11 European countries said that about 16 per cent of expectant mothers overall reported drinking some alcohol, ranging from 29 per cent in Britain, 27 per cent in Russia and 21 per cent in Switzerland, to just over four per cent in Norway.

Earlier this year, British Pregnancy Advisory Service, which offers help to pregnant women, urged officials not to “overstate the risks from consuming small amounts of alcohol during pregnancy”.

In France, winemakers took issue with the government over plans to enlarge a pregnancy alcohol warning on wine bottles, and activists took to social media to accuse the authorities of “terrorising” pregnant women.

The Hong Kong Centre for Health Protection warns: “Pregnant women who drink alcohol have higher chance of giving birth to babies with birth defects, growth and developmental problems.”

The latest paper, based on a review of 26 studies with relevant data, does not resolve the lack of clarity.

It found “some evidence” that drinking up to four units of alcohol per week may be associated with a higher risk of having a smaller baby or giving birth prematurely – but nothing conclusive.

“We were surprised that this very important topic was not researched as widely as expected,” says study co-author Loubaba Mamluk of the University of Bristol’s School of Social and Community Medicine.

“In the absence of strong evidence, advice to women to steer clear of alcohol while pregnant should be made on the basis that it is a precautionary measure and is the safest option,” she says.

However, women who have had a drink while pregnant, perhaps unwittingly, “should be reassured that they are unlikely to have caused their baby considerable harm,” the team write.

Experts not involved in the study welcomed its contribution to the limited knowledge pool.

While it does not say light drinking is safe, the research does highlight the weak evidence on which government advice is based, they say.

James Nicholls, research director at the charity Alcohol Research UK, says the findings “should caution us not to create a situation where mothers-to-be are made more anxious, or subject to unnecessary moral judgment, on the issue of very light alcohol consumption.”

David Spiegelhalter of the University of Cambridge says, “with luck this should dispel any guilt and anxiety felt by women who have an occasional glass of wine while they are pregnant.” AFP