Evening Primrose Oil & Overall Fertility

I'm proud to post this guest blog from a German nutrition student who interned with me last year. During her time with me she researched and wrote about evening primrose oil and fertility.

By: Andrea Kienle (Student of Bachelor of Science in Nutrition, University of Applied Science Fulda)

A balanced diet should accompany us at every stage of our lives. But there is a time in which we are more aware of the importance of balance: during pregnancy. During this time, many women change their eating habits, give up alcohol and take prenatal supplements folic acid and iron. But what if you plan to get pregnant and want to prepare for a healthy pregnancy? These days, many women move their plan to start a family later – and realize that it is more difficult to get pregnant. If you are in this situation, you probably want to improve everything you can for conception. Many food supplements offer to enhance fertility, but what does the scientific side look like? Do the products keep their promises? One commonly used supplement is Evening Primrose Oil (EPO). This supplement is advertised to increase and enhance the quality of cervical mucus and thereby help the sperm get to the egg.

So, let´s take a closer look at the composition of EPO. The botanical name for EPO is Oenothera biennis L. and the supplement industry uses the seeds. It`s health-promoting effects are attributed to its composition of gamma-linoleic acids and phytosterols (Montserrat-de la Paz et al. 2014). Plant-based gamma-linoleic acids are omega-6 fatty acids with anti-inflammatory properties (Horrobin 1981). Phytosterols may reduce cholesterol. Nevertheless, the evidence doesn´t show that EPO helps improve fertility. So far, there have been no studies that look for improvements in the cervical mucus. You may ask yourself what role does the cervical mucus play for conception? During most of the month, the cervical mucus prevents conception by preventing sperm from reaching the uterus. Right before ovulation it changes consistency to allow the sperm to reach the egg. Thus, the cervical mucus is a practical sign of ovulation, which women use to recognize ovulation (Owen 2013).

Certainly, women have used EPO and gotten pregnant. But, we have no evidence that EPO made this happen any faster than it would have without it. To recommend a supplement, we need randomized controlled trials where the effectiveness of medications is compared to placebo. And of course, we can´t forget that supplement companies aim to make money. The National Health Statistics Reports show that Americans spent 12.8 billion dollars in 2012 for natural product supplements. This market gets bigger and bigger every year in today´s food culture (Nahin et al. 2016), and if a product sounds too good to be true, it probably is.  

So, what are the best recommendations for conception?

One study from 2007 speaks about a “fertility diet” which may influence fertility positively in otherwise healthy women. But what does the term “fertility diet” mean (Chavarro et al. 2007)?

One part of this diet is replacing animal sources of protein like red meat, chicken and turkey with vegetable sources of protein. Even one serving of meat per day can increase the risk of developing ovulatory infertility by more than 30 % of women (Chavarro et al. 2008).

Vegetable sources of protein, Source: USDA 2017

Legumes: Tofu (fried) 3oz. (85g) = 16 g
                 Lentils (cooked) 1 cup (198g) = 18g
                 Peanuts (unsalted) 1 cup (131g) = 25,5g

Nuts: Cashew (unsalted) 1oz. (28g) = 4g
          Almonds (unsalted) 1oz. (28g) = 6g
          Walnuts (unsalted) 1oz. (28g) = 7g

Cereals: Whole wheat bread: 1 slice (32g) = 4g
              Oats (dry) = 1/3 cup (28g) = 4g
              Quinoa (cooked): 1 cup (185g) = 8g

Furthermore, to improve fertility, trans fatty acids such as in some French fries, croissants, and granola bars should be strictly removed from the diet. Simply put, the risk of ovulatory infertility increases with the amount of trans fats in your diet up to over 70 % (Chavarro et al. 2007a). Spice up your salad with cold pressed olive oil or flax seed oil to get lots of healthful fats.  

Sources of mono- and polyunsaturated fatty acids

Monounsaturated fatty acids: Olive oil

Polyunsaturated fatty acids: Flax seed oil, walnut oil

Mono- and polyunsaturated fatty acids: Avocado

For fertility, high-fat dairy foods are preferable, as low-fat dairy foods may increase the risk of an ovulatory infertility whereas high-fat dairy products may decrease it (Chavarro et al. 2007b).

What else can you do to improve fertility?

Combine a “fertility-friendly” diet with weight management and regular physical activity to reduce your risk of ovulatory disorder infertility more than 60 % (Chavarro et al. 2007). It’s also important to take a multivitamin supplement with B vitamins, in particularly folic acid 3 to 6 times per week (Chavarro et al. 2008).

My personal recommendation is: instead of spending lots of money for a supplement with cheap promises, invest this money in a private consultation with a Registered Dietitian Nutritionist. Here, you can get a detailed look at your personal needs and receive evidence-based recommendations.

Sources Cited:

  • Biesalski, H.K., Bischoff, S.C., Puchstein, C.: Ernährungsmedizin: Nach dem Curriculum Ernährungsmedizin der Bundesärztekammer, 4. Auflage, Stuttgart 2010
  • Chavarro, J.E., Rich-Edwards, J.W., Rosner, B.A., Willett, W.C. (2007): Diet and lifestyle in the prevention ovulatory disorder infertility. Obstet Gynecol 2007 Nov; 110(5):1050-8
  • Chavarro, J.E., Rich-Edwards, J.W., Rosner, B.A., Willet, W.C. (2007a): Dietary fatty acid intakes and the risk of ovulatory infertility. The American Journal of Clinical Nutrition
  • Chavarro, J.E., Rich-Edwards, J.W., Rosner, B., Willett, W.C. (2007b): A prospective study of dairy foods intake and anovulatory infertility. Human Reproduction Vol. 22, No.5 2007
  • Chavarro, J.E., Rich-Edwards, J.W., Rosner, B.A., Willett, W.C. (2008): Use of multivitamins, intake of B vitamins and risk of ovulatory infertility. Fertil Steril. 2008 March; 89(3): 668-676
  • Chavarro, J.E., Rich-Edwards, J.W., Rosner, B.A., Willett, W.C. (2008): Protein intake and ovulatory infertility. Obstet gynecol 2008
  • Collins, A., Cerin, A., Coleman, G. Landgren, B.M. (1993): Essential fatty acids in the treatment of premenstrual syndrome. Obstet Gynecol 1993
  • Horrobin DF: The importance of gamma-linolenic acid and prostaglandin E1 in human nutrition and medicine. J Holistic Med 1981;3:118-39
  • Lane K., Derbyshire, E., Li W., Brennan C. (2013): Bioavailability and potential uses of vegetarian sources of omega-3 fatty acids: a review of the literature, Crit Rev Food Sci Nutr. 2014
  • Montserrat-de la Paz, S., Fernandez-Arche, A., Angel-Martin, M., Dolores Garcia-Gimenez, M. (2012): The sterols isolated from Evening Primrose oil modulate the release of proinflammatory mediators, Phytomedicine 19 (2012), 1072-1076, Elsevier
  • Montserrat-de la Paz S., Fernandez-Arche, M.A., Angel-Martın, M., Gimenez, M.D. (2014): Phytochemical characterization of potential nutraceutical ingredients from Evening Primrose oil (Oenothera biennis L.), Phytochemistry Letters 8 (2014) 158–162, Elsevier
  • Nahin, R.L., Barnes, P.M., Stussman, B.J. (2016): Expenditures on Complementary Health Approaches: United States, 2012, National Health Statistic Reports No. 95, 2016
  • Owen, M. (2013): Physiological signs of ovulation and fertility readily observable by women.The Linacre Quarterly Vol. 80
  • USDA (2017): United States Department of Agriculture. Agricultural Research Service: National Nutrient Database for Standard Reference Release. URL: https://ndb.nal.usda.gov/ndb/search/list?qlookup=&qt=&manu=&fgcd=&SYNCHRONIZER_URI=%2Fndb%2Fsearch%2Flist&SYNCHRONIZER_TOKEN=3e7b4362-812a-400d-98f6-f2e10fcc116a&ds=Standard+Reference (access:03/11/2017)
  • Thompson, J. L., Manore, M.M., Vaughan, L.A.: The Science of Nutrition, Fourth Edition, United States of America 2015
  • Yakoot, M., Salem, A., Omar, A.M. (2011): Effectiveess of a herbal formula in women with menopausal syndrome. Forsch Komplementmed 2011
Posted on February 28, 2018 .

Health Without Willpower

Have you ever complained that you “just don’t have willpower?” If you can easily choose a healthy, balanced meal for lunch and dinner but later eat a half block of cheese  or way too many snacks on the couch watching TV at night- I’m writing for you.

Research suggests you don’t have a never-ending supply of willpower. Using your willpower in one area affects how much you have left for another area- there aren’t separate buckets of food willpower and work willpower and family willpower.

Why is this important for eating? If you work hard all day to "eat healthy" you may eat too much at night because you run out of willpower. Maybe you used it up choosing that salad at lunch when you wanted a sandwich, being nice to that jerk at work, talking kindly to your kids when you wanted to yell, and sitting calmly through traffic when you want to scream.

Changing your food environment and the way you put together your meals can help.  A lot of research has focused on the way our homes, work and schools are set up and how this impacts our eating. For tons of ideas and details check out these two books by my research hero, Brian Wansink.

Slim by Design

Mindless Eating, Why We Eat More Than We Think

If you want the quick version, I'm here for you. Below I listed out some tips and tricks for meals and snacks with both the environment and your fullness and satisfaction in mind. My goal is to help you save your willpower for the hard stuff- like eating only one brownie from the free food table at work. 

There are a lot of ideas here, because different things work for different people. Research suggests that people are more successful when they pick a couple of small changes and stick to them instead of trying a lot of different things.

I recommend you pick and write down 1-3 ideas from the list below that you think will work for you. Put them somewhere visible every day and focus on one per week.

Of course, there’s nothing like your own personal dietitian, so for individualized help, come see me in personIn our visit I help you think about your strengths, weaknesses and eating patterns. Together, we create a plan just for you. I also help you follow through, checking in regularly to troubleshoot what is and is not working. 


  • Use a reasonably sized bowl and small spoon- we eat less when we use smaller bowls and smaller utensils. No mixing bowls or soup spoons!
  • Take your time. Do the hard work of getting up early enough that you have at least 20 minutes to sit and eat breakfast. Any shorter and your stomach doesn’t have time to tell your brain you’re full so you don't know to stop eating. 
  • Make changes slowly. If you’re trying to limit the sugar and cream in your coffee, start by using a little less sugar, then whole milk, then  2%, etc. Drastic changes are hard - be nice to your taste buds and give them time to adapt. You’re more likely to go right back to full cream and sugar if that black coffee tastes terrible.

If you eat hot or cold cereal

  • Add whole fruit (1/2-1 cup) and nuts (1/4 cup) first- these will give you the fiber, healthy fat and protein you need to stay satisfied until your next meal or snack.
  • Make it easy to stick to healthy portions by using extra measuring cups as scoops in nuts and granola. Did you know the nutrition facts on granola tell you what's in 1/4 cup- yikes that's a small amount!
  • Keep only a few healthy and tasty cereals in the house, so you can feel good about making any choice- even if it’s the kids' cereal.

Morning Snack

  • If you’re hungry 2-3 hours after breakfast, that means you didn’t eat enough breakfast, or didn’t eat the right stuff to keep you satisfied (protein, fiber, and healthy fats). A good breakfast should get you at least 3 hours of satisfaction, but for most people it’s 4-5 hours.
  • If you crave carbohydrates like sweets, pretzels, chips- see eating the right stuff above- carb cravings are your body’s way of telling you that your blood sugar is low. Don’t blame yourself- your body is giving you good information!
  • Be prepared. If you’re lucky enough to have space to store snacks at work, take advantage! If you have trouble managing your portions- try single serve packages. A couple of ideas are below- but there's lots of options that work!
  • If you have a fridge: foods like fruit with greek yogurt, string cheese, cottage cheese or hard boiled eggs or sliced veggies with hummus or guacamole might be a good fit.
  • Without a fridge: foods like banana or apple with peanut butter, lara bar, a small pack of trail mix or nuts might work.
  • Make it a mini meal. A satisfying snack will have protein or healthy fat as well as a fruit, veggie or other carbohydrate.


  • Be prepared. Sounding familiar- this piece is key! If your lunch is packed and ready to go, you don’t have to work your willpower making healthy choices at lunch- you only have one choice!
  • Include fiber, protein and healthy fat to stay satisfied. Some crunchy veggies, a piece of fruit, whole grains and lean protein make for a balanced and tasty meal.

Office candy dishes

  • Keep that dish opaque (instead of clear) and away from your desk! These two changes might just save you over 100 extra calories per day, which over 7 weeks would be an extra pound’s worth!
  • If you do eat candy- don’t throw away the wrappers as you go. Visual cues show you how much you’ve eaten, so keeping the evidence close by helps you eat less. You’re not a slob, you just care about your health!

Afternoon Snack

  • Don’t be afraid to have one if you get hungry. Many people avoid snacking if they’re trying to manage their weight, but if you get home too hungry, you probably eat too much before dinner, or eat too much or too quickly at dinner. Save that willpower! Don’t head home hungry, tired and cranky (HANGRY!)
  • See Morning snack above for ideas.

While Cooking Dinner

  • Be prepared. To avoid overeating now, have a tupperware of pre-cut veggies you cut up over the weekend or bought at the store. If you need a dip, grab some hummus or light dressing (I like Bolthouse Farms Yogurt dressings).


  • Put less on your plate. You will eat ~90% of what you serve yourself, so start light. Give yourself permission to get seconds.
  • Eat ½ a plate of non-starchy vegetables. The fiber in these crunchy veggies helps keep you satisfied without a lot of calories. It also adds color, vitamins and minerals to your meal. The starchy ones are peas, corn, potatoes, acorn squash- the less crunchy texture gives them away. They're healthy foods too- but better in smaller amounts.
  • Serve in the kitchen. People eat when they see food- so keep most of the food off the table and out of your immediate line of sight. If you’re trying to eat more veggies, put these on the table, you’re likely to eat more. So eating right from the pot is out :). 


  • Because of the horizontal-vertical illusion, people with shorter wider glasses drink more than those with taller, thinner glasses, but think they are drinking less.

Desserts and Snacks

  • Serve sweets in small bowls. One cup of ice cream can be 500 or more calories. One cup looks sad and lonely in a bowl that would hold three. Get a small bowl to fill and you won’t feel like you’re sacrificing. It’s not just you! Nutrition graduate students and faculty who used a larger serving spoon with a larger bowl served themselves over 50% more!
  • Don’t eat from the bag or box. I know it means you have to do more dishes (sigh), but it’s worth it on this one. A bowl has a natural stopping point where you have to think about whether you want more and whether it’s worth getting off the couch to get it. It’s nighttime- allow yourself to be lazy – it means you eat less snack food!


  1. Kirsikka Kaipanen, Collin R. Payne, and Brian Wansink, "The Midless Eating Challenge: Retention, Weight Outcomes and Barriers for Changes in a Public Web-based Eating and Weight Loss Program,"Journal of Medical Internet Research. 14, no. 6 (2012): e168.
  2. Brian Wansink and David R. Just (2014). "Trayless Cafeterias Lead Diners to Take Less Salad and Relatively More Dessert," Public Health Nutrition
  3. Wansink, B. (2014). Slim By Design: Mindless Eating Solutions for Everyday Life. New York, NY: William Morrow
  4. Ellen Van Kleef, Mitsuru Shimizu, and Brian Wansink, "Serving Bowl Selection Biases the Amount of Food Served,"Journal of Nutrition Education and Behavior 44, no 1 (2012): 66-70.
  5. Wansink, B., Painter, J. E., & Lee, Y. K. (2006). The office candy dish: proximity's influence on estimated and actual consumption. Int J Obes (Lond), 30(5), 871-875. doi: 10.1038/sj.ijo.0803217
  6. Wansink, B., Painter, J. E., & North, J. (2005). Bottomless bowls: why visual cues of portion size may influence intake. Obes Res, 13(1), 93-100. doi: 10.1038/oby.2005.12
  7. Wansink, B. (2004). Environmental factors that increase the food intake and consumption volume of unknowing consumers. Annu Rev Nutr, 24, 455-479. doi: 10.1146/annurev.nutr.24.012003.132140;  
  8. Wansink, B., van Ittersum, K., & Painter, J. E. (2006). Ice cream illusions bowls, spoons, and self-served portion sizes. Am J Prev Med, 31(3), 240-243. doi: 10.1016/j.amepre.2006.04.003
  9. Brian Wansink, “Can Package Size Accelerate Usage Volume?” Journal of Marketing 60, no. 3 (July 1996): 1-14.
  10. Brian Wansink and Katherine Abowd Johnson, “The Clean Plate Club: About 92% of Self-Served Food is Eaten,” International Journal of Obesity, forthcoming.
  11. Wansink, B. (2014). "Slim By Design: Mindless Eating Solutions for Everyday Life." New York, NY: William Morrow
  12. Collin, Payne, Laura E. Smith, and Brian Wansink, “Dish Here, Dine There: Serving Off the Stove Results in Less Food Intake than Serving Off the Table,” FASEB Journal (2010): 878.7.

Posted on June 9, 2016 .

Smoothies for Summer

Want a meal you can grab on the go? Something to do with the leftover fruit and yogurt in your fridge? Smoothies can fit the bill. Not all smoothies are created equal, but smoothies can be both healthy and delicious. Check out the blog post for a design your own smoothie matrix, recipes and more.

Posted on May 27, 2016 .

Keep the Weight Off: Lessons learned from the NWCR

The National Weight Control Registry (NWCR) is a research study that looks at the habits of people who have successfully lost weight and kept it off. On average the people in this study have lost about 70 lbs and kept the weight off for about 5 years, but all people in the study have lost at least 30 lbs and kept it off for at least 1 year. I've looked at the most recent research from this study and broken the things these people do into Six Steps to Keep the Weight Off. 

Posted on August 17, 2014 .