January 28, 2013
Fruit And Vegetables Today Predict Mood Tomorrow
Tracking mood and diet by a daily internet survey shows fruits and vegetables make people happier.
A total of 281 young adults (with a mean age of 20 years) completed an internet-based daily food diary for 21 consecutive days. Prior to this, participants completed a questionnaire giving details of their age, gender, ethnicity, weight and height. Those with a history of an eating disorder were excluded.
Gotta love the power of the internet for running studies on what makes humans tick.
On each of the 21 days participants logged into their diary each evening and rated how they felt using nine positive and nine negative adjectives. They were also asked five questions about what they had eaten that day. Specifically, participants were asked to report the number of servings eaten of fruit (excluding fruit juice and dried fruit), vegetables (excluding juices), and several categories of unhealthy foods like biscuits/cookies, potato crisps, and cakes/muffins.
Do you want to feel calmer, happier, and more energetic
The results showed a strong day-to-day relationship between more positive mood and higher fruit and vegetable consumption, but not other foods.
"On days when people ate more fruits and vegetables, they reported feeling calmer, happier and more energetic than they normally did," says Dr Conner.
One day's diet predicts the next day's positive mood. Eat for tomorrow.
To understand which comes first – feeling positive or eating healthier foods – Dr Conner and her team ran additional analyses and found that eating fruits and vegetables predicted improvements in positive mood the next day, suggesting that healthy foods may improve mood. These findings held regardless of the BMI of individuals.
"After further analysis we demonstrated that young people would need to consume approximately seven to eight total servings of fruits and vegetables per day to notice a meaningful positive change. One serving of fruit or vegetables is approximately the size that could fit in your palm, or half a cup. My co-author Bonnie White suggests that this can be done by making half your plate at each meal vegetables and snacking on whole fruit like apples," says Dr Conner.
Gotta eat some cauliflower before I go to sleep tonight.
Randall Parker, 2013 January 28 10:18 PM
Do you own a juicer? You can get in 10 servings of vegetables quite easily. I know the survey excluded the effects of vegetable juice, but a lot of people report positive results from juicing daily.
The moment I read this I post I realized that, unlike usual, I hadn't had any F&V all day. So I put down the bagel I was snacking on and immediately downed 8 servings: 2 little cans of V-8, a carrot, spinach, green beans, and a smoothie worth probably 3 servings. It took maybe ten minutes, and I don't even feel stuffed. I'll have to see how tomorrrow goes and report back.
The problem with trying to live a healthy lifestyle is that the rewards are often gradual, delayed, or both. But the results of this study certainly validate what I've found in my own life. My mood goes up and down, but I'm living a much healthier lifestyle than I was 10 years ago, and I'm pretty sure I'm a lot happier than I was then.
One thing I wonder is if the improvements in mood are entirely the result of F&V consumption, or also the result of not eating unhealthier foods because you've filled yourself on produce. A person eating 8 servings worth of F&V is almost certainly eating less junk food.
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The effects noted in the study may be simply due to the potassium in fruits and vegetables. Either potassium consumption by itself, or perhaps the ratio of potassium to sodium might be important. A 2008 paper "Dietary electrolytes are related to mood" found positive effects of a high potassium, low sodium diet (British Journal of Nutrition, 100(5):1038-45). For those wanting to test this out for themselves, look on your supermarket shelves for Low Sodium V-8 juice. This has 850 mg potassium but only 135 mg sodium per glass. For those skeptical about why sodium and potassium should affect mood, remember that lithium which is in the same column in the periodic table as sodium and potassium is a mood stabilizing agent and is widely used to treat bipolar disorder.
Bruce, I'm a regular consumer of low sodium V-8 - on the order of two servings a day, 5-6 days a week. I haven't noticed that it improves my mood *that* much. Having spent much of my younger days with significant mood/health issues, my personal experience with health and mood is that 4 things matter most: 1) adequate sleep (7-8 hours); 2) regular exercise (cardio AND strength training; 3) proper diet - i.e., plenty of fruits and vegetables, and not too much junk food; and 4) adequate hydration. Each person can have issues affecting them specifically, but those are probably the big four.
I'm glad I'm not the only one who noticed the effects of hydration on mood. I would love to see some studies on it.