This is one of the largest ever studies looking at the connection between depression and taking the combined contraceptive pill.
Those that made the change were less depressed and anxious as well as feeling less fatigue.
Vegetarian and vegan diets are linked to a reduced risk of depression and anxiety, multiple studies have found.
Plus, there is no need to be strict: altering food intake towards a more plant-based diet may still provide a boost to mental health.
One study carried out in the US involved half of 292 people being given weekly instruction in following a vegan diet.
Over the 18 weeks of the study, all had access to healthy vegan options at work for their lunch.
These included black bean chilli, leafy green salads and vegetable hummus sandwiches.
After four months, those that made a shift towards being more vegan were less depressed and anxious as well as feeling less fatigue.
They also felt their overall health was better.
Dr Neal Barnard, study co-author, said:
“The same foods that curb the risk for obesity, heart disease, and diabetes, may help boost overall mood.
In the evolving landscape of neurological research, a plant-based diet may help in treating symptoms of anxiety and depression.”
Vegetarian diets may also provide a similar boost to mental health as vegan diets.
Another study of 15,093 people in Spain found that a pro-vegetarian eating pattern was linked to lower levels of depression.
One nice thing to emerge from this study was that becoming moderately vegetarian was as good as being a strict vegetarian for depression.
Again, people did not have to become completely vegetarian to see the benefit, just lean in that direction.
Health benefits of plants
The health benefits of plant-based diets are also well-known, reducing the risk of heart disease, cancer and other illnesses.
According to one review of 86 separate studies:
“This comprehensive meta-analysis reports a significant protective effect of a vegetarian diet versus the incidence and/or mortality from ischemic heart disease (-25%) and incidence from total cancer (-8%). Vegan diet conferred a significant reduced risk (-15%) of incidence from total cancer.”
Note that some studies, like this one, have linked vegetarianism to increased depression, although these are in the minority.
The studies were published in the journals American Journal of Health Promotion, BMC Medicine, Critical Reviews in Food Science And Nutrition (Agarwal et al., 2015; Sánchez-Villegas et al., 2015; Dinu et al., 2017).
People in the study had been diagnosed with major depressive disorder and were already taking antidepressants.
Very common vitamin deficiency linked to higher levels of depression.
Almost half of young women have insufficient vitamin D levels, which is linked to depression.
The study also found that over one-third of young women had signs of clinical depression.
Dr David Kerr, the psychologist who led the study, said:
“Depression has multiple, powerful causes and if vitamin D is part of the picture, it is just a small part.
But given how many people are affected by depression, any little inroad we can find could have an important impact on public health.”
While many suspect a link between the vitamin deficiency and depression, studies have not often confirmed it.
Dr Kerr continued:
“The new study was prompted in part because there is a widely held belief that vitamin D and depression are connected, but there is not actually much scientific research out there to support the belief.
I think people hear that vitamin D and depression can change with the seasons, so it is natural for them to assume the two are connected.”
To test the link researchers recruited 185 female college students between the ages of 18-25.
The study focused on women because they are almost twice as likely to suffer from depression.
Their vitamin D levels were measured from their blood.
Depression symptoms were checked every week for five weeks.
The results showed that women of colour had particularly high vitamin deficiency for vitamin D, with 61% being deficient.
This compared to low vitamin D levels in 35% of other women.
Vitamin D is important for both mental and physical health.
Physically, it has been linked to better bone health, muscle function, and cardiovascular health.
Vitamin D is created in the body with exposure to sunlight.
It is also found in some foods, like milk, which is fortified with it.
Dr Kerr concluded:
“Vitamin D supplements are inexpensive and readily available.
They certainly shouldn’t be considered as alternatives to the treatments known to be effective for depression, but they are good for overall health.”
The vitamin deficiency study is published in the journal Psychiatry Research (Kerr et al., 2015)
Transcranial magnetic stimulation or TMS can be beneficial for people whose depression does not respond to other treatments.
These foods make up about 60 percent of all calories consumed by Americans.
Gamma waves, which repeat upwards of thirty times every second, help the brain communicate effectively between regions.
Could there be a ‘dimmer switch’ for depression?
People who are depressed may have hyperactivity in a part of the brain known as ‘the disappointment circuit’, a study finds.
Scientists led by Professor Roberto Malinow of the University of California, San Diego, found what could amount to an antidote to feeling let-down.
The study focused on a part of the brain called the lateral habenula, which has been linked to the feeling of disappointment which follows from the absence of an expected reward.
Professor Roberto Malinow, who led the study, said:
“The idea that some people see the world as a glass half empty has a chemical basis in the brain.
What we have found is a process that may dampen the brain’s sensitivity to negative life events.”
The neuroscientists found that this area, unlike almost any other in the brain, produces neurotransmitters which both ramp up and damp down brain activity.
Dr Steven Shabel, the study’s first author, said:
“Our study is one of the first to rigorously document that inhibition can co-exist with excitation in a brain pathway.
In our case, that pathway is believed to signal disappointment.”
The study may help to explain why people experiencing depression tend to concentrate so much on negative events.
Depression has already been linked to hyperactivity in the lateral habenula in previous studies.
Until now, though, scientists have not understood how the brains of healthy individuals damp down activity in the so-called disappointment circuit.
Dr Shabel said:
“The take-home of this study is that inhibition in this pathway is coming from an unusual co-release of neurotransmitters into the habenula.
Our study suggests that one of the ways in which serotonin alleviates depression is by rebalancing the brain’s processing of negative life events vis-à-vis the balance of glutamate and GABA in the habenula.
We may now have a precise neurochemical explanation for why antidepressants make some people more resilient to negative experiences.”
The study was published in the journal Science (Shabel et al., 2014).
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