Feed your microbes to deal with stress: a psychobiotic diet impacts microbial stability and perceived stress in a healthy adult population

The impact of diet on the microbiota composition and the role of diet in supporting optimal mental health have received much attention in the last decade. However, whether whole dietary approaches can exert psychobiotic effects is largely understudied. Thus, we investigated the influence of a psychobiotic diet (high in prebiotic and fermented foods) on the microbial profile and function as well as on mental health outcomes in a healthy human population. Forty-five adults were randomized into either a psychobiotic (n = 24) or control (n = 21) diet for 4 weeks. Fecal microbiota composition and function was characterized using shotgun sequencing. Stress, overall health and diet were assessed using validated questionnaires. Metabolic profiling of plasma, urine and fecal samples was performed. Intervention with a psychobiotic diet resulted in reductions of perceived stress (32% in diet vs. 17% in control group), but not between groups. Similarly, biological marker of stress were not affected. Additionally, higher adherence to the diet resulted in stronger decreases in perceived stress. While the dietary intervention elicited only subtle changes in microbial composition and function, significant changes in the level of 40 specific fecal lipids and urinary tryptophan metabolites were observed. Lastly, microbial volatility was linked to greater changes in perceived stress scores in those on the psychobiotic diet. These results highlight that dietary approaches can be used to reduce perceived stress in a human cohort. Using microbiota-targeted diets to positively modulate gut-brain communication holds possibilities for the reduction of stress and stress-associated disorders, but additional research is warranted to investigate underlying mechanisms, including the role of the microbiota.


List of Foods to Include
Fruits (3 servings/day) and Vegetables (6 servings/day) How can you use these foods in your diet?
• Aim for eating 6-9 servings of fruits and vegetables per day. Most of these should include the fruits and vegetables listed above. • Fruit: Eat a whole apple or slice it up and eat with your cereal or oat. It also makes a great addition to smoothies with other fruits. For example, you can add some Kefir and fruits in a blender and make a smoothie rich in prebiotics • Vegetables: Oven roasted vegetables are easy to make and add an extra crunch. You can also add some fresh garlic which enhances taste and adds additional prebiotics. • Grains: Consume whole grains instead of refined grains (e.g., white bread). • Sprinkle Chia seeds or flax seeds on your salad on in yogurt or with your oats. You can also add some berries to increase the flavour. • Kefir: If the Kefir is too bitter, you can make a smoothie by adding some fruit and spices such as cinnamon or a little bit of cocoa. • Legumes: Quinoa, barley and chickpeas are great additions to salads. Here you can also add some onions and other vegetables to enhance the flavour and adding more prebiotics. • You can buy canned chickpeas for easy use. Quinoa and barely have to be cooked before use. However, just like boiling rice, it is very easy to prepare. You can also find prepared food with quinoa which are easier to use. • Instead of chickpeas, you can also eat hummous. Pair them with crackers that are made of whole wheat or quinoa and other grains. • Nuts: A handful of nuts make a great snack for in-between meals.
• Kombucha is a fermented black or green tea. You can enjoy it with your meal or as a drink to sip on during the day. • Sauerkraut can be enjoyed in various different ways. Try adding it to soups, casseroles, sandwiches or simply enjoy it with some mashed potatoes. • Leeks and cabbage: Prepare a stir fry as a delicious way to enjoy leeks and cabbage.
You can also add some onions and garlic for more flavour.

Estimating serving sizes
Use a disposable plastic cup to guide portion sizes of grains and cereal, vegetables and beverages Vegetables 1 serving equals ½ disposable 200 mL cup cooked or raw vegetables, 1 disposable 200 mL cup of leafy vegetables Fruit 1 serving equals 1 medium piece of fruit (i.e., apple), 2 smaller size fruit (i.e., mandarins), 10 grapes, 6 strawberries, ½ cup blueberries Grains, Nuts and Legumes 1 serving equals 1 slice of whole wheat bread, 2 breakfast wheat or oat biscuits, 1/3 cup of raw porridge oats, 6 wholemeal crackers, 1 cup sweet potatoes or ½ cup of cooked whole wheat pasta or brown rice Handful (30g) of nuts, 1-2 teaspoons of peanut butter, 2-3 tablespoons of seeds ½ disposable 200 mL cup of lentils, beans or chickpeas

Preparation:
1. Combine all ingredients (ground beef, tomato paste, garlic, herbs, salt, pepper, chia seeds) in a bowl. Let rest for 10 minutes. 2. Scoop 8 balls and pat into a round shape 3. Heat a large skillet over medium heat and add the oil. Cook meatballs until brown, turning on at least 3 sides. Move meatballs to a place to rest (they will not be fully cooked yet, but will finish cooking later in the sauce. 4. In the same pan, add the onion and sauté until translucent (3-5 minutes). Add garlic and seasoning. 5. Add stock, diced tomatoes, and tomato sauce and cook over medium heat until sauce begins to thicken (15-20 minutes). 6. Reduce heat to medium low and add meatballs. Cook 5-10 minutes or until meatballs are cooked through. 7. Serve with whole grain spaghetti or try spiralized vegetables (such as courgettes).

Preparation:
7. Place sauerkraut in a colander and rinse with cold water. Drain well and press out excess liquid. 8. Coat one side of the bread with butter. Top the other side with chicken, sauerkraut, apple slices and cheese. 9. Preheat a grill pan and add sandwiches. Use a spatula to press the sandwiches down, cooking 6 to 8 minutes on each side or until bottoms are toasted.
(Source: http://www.eatingwell.com/recipe/259852/chicken-sauerkraut-and-apple-panini/) 10. Place chickpeas in a mixing bowl and add the tahini. Mash up the chickpeas with fork or potato masher until almost smooth. 11. Fold in the remaining ingredients and season to taste. 12. Place carrots and spinach on the wrap and top with the chickpea sauerkraut salad. Tip:

Chickpea Salad Wrap with Sauerkraut
heat up the wrap in the microwave to make it soft at pliable, if desired.

Preparation:
13. Preheat oven to 180º C. 14. In a large skillet, cook ground beef, onion and green pepper until meat is no longer pink. 15. Stir in diced tomatoes, vinegar, and garlic powder. 16. Simmer, uncovered, for 10 minutes. Season to taste and set aside. 17. Put about 3 cm of water and a pinch of salt in a large saucepan. Add the cabbage and bring to a boil. Reduce heat to medium low, cover and cook for about 10 minutes. Drain thoroughly. 18. Arrange cabbage in a casserole pan. Pour ground beef mixture over cabbage and bake uncovered for 20-25 minutes. 19. Sprinkle cheese over the casserole and bake for another 5 minutes, until cheese has melted.

Mediterranean Salad
Ingredients: • 20. In a salad bowl toss together tomatoes, chickpeas and cucumber. 21. Add avocado and feta and toss gently. 22. Add olive oil, lemon juice, garlic and basil and toss until evenly coated.

Preparation:
1. Spread the Thousand Island dressing on both slices of bread. Then put the corned beef on one slice and top it with sauerkraut and the cheese. 2. Heat sandwich in a sandwich maker or frying pan. If using frying pan, put butter in the pan, press sandwich down onto the pan with a spatula and health for 3-4 minutes from each side until the bread is browned and the cheese has melted.

Preparation:
23. Rinse quinoa under cold water and prepare according to package instructions. Transfer to a bowl to cool. 24. In another bowl, combine the oil, lemon juice and vinegar with some seasoning. 25. Once quinoa has cooled, mix with the dressing and remaining ingredients.

Whole grain bread with scrambled eggs, avocado and sauerkraut
Ingredients:

Preparation:
3. Cut the avocado in half, scoop it out and spread it on the bread. Tip: You can toast the bread to give it some extra crunchiness. 4. Add a layer of sauerkraut. You can use as much or as little as you want. 5. Scramble your eggs. Season with salt and pepper or other seasonings to taste. Then top the sandwich with the scrambled eggs. 6. Tip: You can add other vegetables (e.g., tomato) or any sauces (e.g., Siracha sauce) to the sandwich to cater it to your taste.

Cheese
Use two thumbs, width and depth to guide serving size.

Meat, poultry, fish
The palm of the hand, width and depth without fingers and thumbs, shows how much you need in a day.

Reduced-fat spread
Portion packs found in cafes can guide the amount you use. One pack should be enough for two slices of bread.

Oils
Use one teaspoon of oil per person when cooking or in salads.

Get Active!
To maintain a healthy weight adults need at least 30 minutes a day of moderate activity on 5 days a week (or 150 minutes a week); children need to be active at a moderate to vigorous level for at least 60 minutes every day.

Drink at least 8 cups of fluid a day -water is best
There is no guideline for inactive children as it is essential that all children are active. Use as little as possible. Choose mono or polyunsaturated reduced-fat or light spreads. Choose rapeseed, olive, canola, sunflower or corn oils. Limit mayonnaise, coleslaw and salad dressings as they also contain oil. Always cook with as little fat or oil as possible -grilling, oven-baking, steaming, boiling or stir-frying.
Choose lean meat, poultry (without skin) and fish. Eat oily fish up to twice a week. Choose eggs, beans and nuts. Limit processed salty meats such as sausages, bacon and ham.
Choose reduced-fat or low-fat varieties. Choose low-fat milk and yogurt more often than cheese. Enjoy cheese in small amounts. Women who are pregnant or breastfeeding need 3 servings a day.
Wholemeal and wholegrain cereals are best. Enjoy at each meal. The number of servings depends on age, size, if you are a man or a woman and on activity levels. Watch your serving size and use the Daily Servings Guide below.* Base your meals on these and enjoy a variety of colours. More is better. Limit fruit juice to unsweetened, once a day.
Needed for good health. Enjoy a variety every day.
Not needed for good health.

For adults, teenagers and children aged five and over
Healthy Food for Life