"Plant-Based Diets for Improved Mood and Productivity"
A 2014 systematic review and meta-analysis of dietary patterns
and depression concluded that a healthy diet pattern was significantly associated
with the reduced odds of depression.
But out of the 21 studies they could find in the medical literature,
they were only able to find one randomized controlled trial,
considered the study design that provides the highest level of evidence.
And it was the study I profiled in "Improving Mood Through Diet",
in which removing meat, fish, poultry and eggs
improved several mood scores in just two weeks.
We've known those eating plant-based tend to have healthier mood states—
less tension, anxiety, depression, anger, hostility and fatigue,
but you couldn't tell if it was cause and effect
until you put it to the test, which they finally did.
But what could account for such rapid results?
Well, eating vegetarian does give you a better antioxidant status,
which may help with depression.
Also, as I've previously addressed,
how consumption of even a single carbohydrate-rich meal
can improve depression, tension, anger, confusion, sadness, fatigue, alertness,
and calmness scores among patients with PMS, but what about long term?
Overweight men and women were randomized into a low carb, high fat diet
or high carb, low fat diet for a year.
By the end of the year, who had less depression, anxiety, anger and hostility,
feelings of dejection, tension, fatigue, better
vigor, less confusion or mood disturbances?
The low carb dieters are represented by the black circles,
and the low fat dieters are represented in the white.
These sustained improvements in mood in the low fat group
compared with the low carb group
are consistent with results from epidemiological studies
showing that diets high in carbohydrate and low in fat and protein
are associated with lower levels of anxiety and depression
and have beneficial effects on psychological well-being.
The overall amount of fat in their diet didn't change in this study, though.
But the type of fat did.
Their arachidonic acid intake fell to zero.
Arachidonic acid is an inflammatory omega-6 fatty acid
that can adversely impact mental health via a cascade of neuroinflammation.
It may inflame our brain.
High blood levels in the bloodstream have been associated
with a greater likelihood of suicide risk, for example,
and major depressive episodes.
How can we stay away from the stuff?
Well, Americans are exposed to arachidonic acid
primarily through chicken and eggs.
But when you remove chicken and eggs, and other meat,
we can eliminate preformed arachidonic acid from our diet.
So while high-quality treatment studies investigating the impact of diet
on depression are scarce, there is that successful 2-week trial,
but even better: How about 22 weeks?
Overweight or diabetic employees of a major insurance corporation
received either weekly group instruction on a whole food plant-based diet
or no diet instruction for five and a half months.
There was no portion size restriction, no calorie counting, no carb counting.
No change in exercise.
No meals were provided, but the company cafeteria did start offering
daily options such as lentil soup, minestrone, bean burritos.
No meat, eggs, dairy, oil or junk, yet they reported greater diet satisfaction
compared with the control group participants who had no diet restrictions.
How'd they do though?
More participants in the plant-based intervention group
reported improved digestion, increased energy, better sleep than usual
at week 22 compared with the control group.
They also reported a significant increase in physical functioning,
general health, vitality, and mental health.
Here are the results presented graphically,
where the plant-based group beat out controls on nearly every measure.
There was also significant improvements in work productivity,
thought to be due in large part to their improvements in health.
So what this study demonstrated was that a cholesterol-free diet is acceptable,
not only in research settings, but in a typical corporate environment,
improving quality of life and productivity at little cost.
All we need now is a large, randomized trial for confirmation,
but we didn't have such a thing, until now.
Ten corporate sites across the country from San Diego to Macon, Georgia.
Same kind of set up as before.
Can a plant-based nutrition program in a multi-center, corporate setting
improve depression, anxiety, and productivity?
Yes. Significant improvements in depression, anxiety, fatigue,
emotional well being, and daily functioning.
Lifestyle interventions have an increasingly apparent role
in physical and mental health, and among the most effective
of these is the use of plant-based diets.