Ask a Dietitian: Potassium, Omegas, Soy, and More - Performance Kitchen

This article is intended for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition.

The many eating options, regimens, and trends we’re exposed to on a daily basis can get seriously overwhelming, especially if you simply want to eat to feel your best. Our brand is known as Performance Kitchen, but what sort of “performance” are we talking about? We don’t always mean athleticism—although we certainly encourage being active. Performance can include feeling more focused, having more available energy, and even getting a better night’s sleep. We want to help all our customers and fans feel their best, so we asked you to send us your most pressing nutrition questions. Then we sought the help of two Registered Dietitians to share their expertise. If you don’t see the topic you want to learn about answered in the roundup below, stay tuned in the coming months, as we’ll be working through the (many) questions we received. Welcome to our first edition of “Ask a Dietitian” with experts Kelly Jones, MS, RD, CSSD, LDN, and Kate Turner, MA, RD, CSSD, CPT.

Meet the Registered Dietitians

Kelly Jones

Kelly is a Registered Dietitian, Media Expert, Public Speaker, and Consultant. Her expertise lies in performance nutrition for pro-athletes and busy, active adults. Via her blog and social media, Kelly provides resources to integrate nutrition, fitness, and sustainability in realistic ways.

Kate Turner

Kate is a Registered Dietitian and personal trainer. She has 7+ years of experience in the field of nutrition as a Wellness Director, Private Nutrition Consultant, Educator, and Public Speaker. She treats each moment as an opportunity to educate, and loves sharing her knowledge and expertise to help improve the lives of others.

This Week’s Nutrition Questions

Question: “Which foods contain the most potassium? I’m trying to lower my blood pressure – what can I eat to do that? And is it true beet juice helps?”

Kelly says:

Many studies on the DASH (Dietary Approaches to Stop Hypertension) diet suggest that increasing potassium, magnesium, and calcium are great goals when trying to lower blood pressure. More whole plant foods rich in potassium can be beneficial, such as potatoes, sweet potatoes, tomatoes, watermelon, leafy greens, black beans, avocados, squash, beets, and pomegranate.

It’s true that beet juice may help manage blood pressure. It delivers nitrates that are metabolized as a natural vasodilator—meaning it dilates blood vessels and improves blood flow to the organs, including the heart. Also, don’t be alarmed if drinking beet juice changes the color of your urine to red—“beeturia” is a common side effect.

While drinking beet juice or eating beets may lower blood pressure, so can a diet rich in naturally occurring nitrates. Celery, cress, spinach, lettuce, celeriac, Chinese cabbage, endive, kohlrabi, leeks, and parsley all contain high levels of nitrates.

Question: “Which vitamins are actually beneficial and worth taking?”

Kate says:

Supplement regimens should be recommended on an individual basis. However, there are a few common nutrients that most people are lacking. The top three supplements I suggest for almost all of my clients are:

  • Omega-3s
    Omega-3 fatty acids are also called essential fats. They support cellular health, offer anti-inflammatory benefits, and may have protective heart health benefits too.
  • Probiotics
    Probiotics support digestive wellness (aka, gut health) which has a large impact on your overall health.
  • Vitamin D3
    An estimated 42% of US adults are deficient in the so-called “sunshine vitamin” which is necessary to absorb calcium and support healthy bones. Studies show that people with higher levels of vitamin D have a lower risk of disease.

Finally, if you have food allergies or sensitivities, you don’t consume a wide variety of fruits and vegetables, or you follow any kind of restrictive diet (i.e. vegan, vegetarian, keto, etc.) then I recommend taking a multivitamin for extra support.

Question: “I have thyroid problems, should I avoid eating tofu or soy products?”

Kelly says:

Before adjusting your diet, speak with your doctor/endocrinologist and get your iodine levels checked. If hypothyroidism (underactive thyroid) is the issue, be aware of goitrogens. If your iodine is low, they may interfere with your thyroid’s ability to produce hormones. Soy and cruciferous vegetables contain goitrogens, but moderate intake is usually fine as long as you have enough iodine.

For those with hypothyroidism, I recommend soy only in moderation (a single cup of soy milk, or a serving of edamame daily). I wouldn’t suggest it more often until we have more research data to inform your choices.

The same goes for cruciferous vegetables, which are foods like broccoli, cauliflower, Brussels sprouts and cabbage. Cooking destroys much of their potential goitrogenic effect. So, even if low iodine is a concern, a few servings a week offers more nutritional benefits than drawbacks.

That’s all for this week! A big thank you to all of you who submitted your questions about nutrition. We look forward to delving into more nutrition concerns and sharing more nutrition knowledge to help you feel your best. Stay tuned for our next edition of “Ask a Dietitian.” If you’d like to send us your own nutrition question, drop us a line at