When you are seeking to improve our gut health and overall wellness through functional medicine, fiber becomes a vital component of the process. Fiber is a type of carbohydrate found in plant foods, but unlike other carbohydrates, the human body can’t digest it. As it passes through the body’s digestive system, it performs many important functions. 

Fiber slows the rate at which food enters your bloodstream and increases the speed at which food exits your body through the digestive tract. It can help lower cholesterol, blood sugar, and insulin levels. It helps eliminate toxins, remove excess estrogen, and balances hormones. It can help prevent obesity and chronic disease, and it reduces the risk of breast and colon cancer. It makes vitamins and minerals, and acts as a food source for the beneficial bacteria that live in the digestive tract. You need fiber to keep you healthy from top to bottom. 

Types of Fiber

Dietary fiber comes from plant foods, including fruits, vegetables, legumes, nuts, seeds, and grains. Plant foods contain two types of fiber—soluble and insoluble.

Soluble Fiber

Soluble fiber dissolves in water and becomes gel-like, which slows down the rate at which food hits the bloodstream, slowing down digestion of glucose, producing a feeling of fullness, and helping with weight control. It decreases the absorption of sugars and fats, helping manage blood sugar and blood fat levels. Soluble fiber serves as a food source for the beneficial bacteria that live in the digestive tract. 

Insoluble Fiber

Insoluble fiber absorbs water, but does not dissolve in water. It helps move food and waste products through the digestive system, promoting regular bowel movements. It provides bulk to the stool and is beneficial in preventing constipation, hemorrhoids, and diverticulitis.

Symptoms of Insufficient Fiber Intake

The Dietary Reference Intake for dietary fiber (soluble and insoluble fiber, combined) is:

Females, age 18-50: 25 grams per day

Females, ages 51 and above: 21 grams per day

Males, ages 18-50: 38 grams per day

Males, ages 51 and above: 30 grams per day 

Consuming too little fiber can cause major repercussions throughout the body, including: 

  • Constipation
  • Diet-related nausea
  • Excessive gas
  • Fatigue or weakness
  • Frequent hunger
  • Hemorrhoids
  • Hypercholesterolemia (high cholesterol)
  • Hyperglycemia (high blood sugar)
  • Increased risk of developing gallstones
  • Irritable bowel syndrome (IBS)
  • Loss of appetite
  • Overeating
  • Upset stomach
  • Varicose veins

Conditions that can Benefit from Soluble Fiber:

  • Cancer (prevention)
  • Excess weight
  • Hypercholesterolemia (high cholesterol)
  • Hyperglycemia (high blood sugar)
  • Hypertension (high blood pressure
  • Irritable bowel syndromes
  • Metabolic syndrome
  • Overweight or obesity

Conditions that can Benefit from Insoluble Fiber:

  • Constipation
  • Loose stools

Sources of Fiber

Dietary fiber comes from plant foods, including fruits, vegetables, legumes, nuts, seeds, and grains. Most plant-based foods contain both types of fiber. For example, the inner portion of an apple contains soluble fiber and the peel is insoluble fiber. 

In order to get the full benefits of fiber, plant foods must be eaten in their whole form, or close to their whole form. 

Plant Sources of Soluble Fiber

  • Apples
  • Apricots
  • Artichokes
  • Asparagus
  • Avocado
  • Bananas
  • Barley
  • Beans (black, lima)
  • Blackberries
  • Broccoli
  • Brussels sprouts
  • Cabbage
  • Carrots
  • Dark, leafy greens
  • Flaxseed
  • Legumes
  • Lentils
  • Nuts
  • Oat bran
  • Okra
  • Oranges
  • Pears
  • Peppers
  • Prunes
  • Psyllium
  • Squash
  • Sweet potatoes

Plant Sources of Insoluble Fiber

  • Bananas
  • Beans (black, kidney, navy)
  • Bran
  • Broccoli 
  • Brown rice
  • Brussels sprouts
  • Carrots
  • Cauliflower
  • Celery
  • Corn
  • Cucumbers
  • Grains
  • Lentils
  • Okra
  • Peas
  • Potatoes (with skin)
  • Prunes
  • Spinach
  • Tomatoes
  • Wheat bran

Increasing Your Fiber Intake

The Institute for Functional Medicine recommends that adults consume about 25 – 35 grams of fiber daily from their food. However, the average American adult eats about half that amount. Tips for incorporating more fiber into your diet include:

  • Try to eat 5 – 10 servings of fresh vegetables or fruit per day. A serving is half a cup of cooked vegetables, one cup of raw or leafy vegetables, or a medium piece of fruit.
  • Including fresh vegetables with each meal and snack is a great way to make sure you reach your daily goal.
  • Choose whole grain rice, breads, and pastas over products made with refined or white flour.
  • Get creative with substitutions. If a recipe calls for animal protein, try making the dish with beans or legumes instead. (This works well with chili, soups, and stews.)
  • Swap juices for smoothies, using the same ingredients. While fresh fruit and vegetable juices contain vitamins and minerals, the fiber is lost in the juicing process. Blending the ingredients into a smoothie will produce a similar taste without losing the beneficial fiber.

Remember: adding too much fiber or adding fiber too quickly can cause bloating, gas, cramps, and diarrhea. When first starting to add fiber into your diet, try adding 5 grams daily in 2-week intervals until you hit your target intake. 

Drink a lot of water when you ingest a large amount of fiber so that you do not become constipated.

Stephanie Ritari, PA-C

Stephanie Ritari is a board-certified Physician Assistant who offers primary care for adults at the Functional Medicine of Idaho Meridian Wellness Center. She specializes in Internal Medicine and has spent the majority of her career in the field of cardiovascular disorders.

Stephanie has more than 15 years experience as a Physician Assistant in a variety of medical areas, including cardiology and electrophysiology. Holistic practices have long been a part of Stephanie’s lifestyle, with a particular focus on clean living and nutrition. She has embedded functional principles into her conventional medicine practice throughout her career. After watching family members struggle to find answers for their chronic illnesses, Stephanie became more interested in finding ways to take a root cause approach in her own practice. Wanting to provide a proactive, comprehensive, and preventative scope of care for her patients, Stephanie began studying functional medicine. In 2021, she joined Functional Medicine of Idaho, where she is able to provide evidence based, root cause medicine.

Stephanie earned her Bachelor's of Science in Exercise Physiology from the University of Montana and her masters in Physician Assistant Studies from Rocky Mountain College. She is currently working towards her certification with The Institute for Functional Medicine. 

In her spare time, Stephanie enjoys spending time with her husband, son, and dog doing outdoor activities including biking, hiking, and skiing. She also loves interior design and traveling, and is hoping to start her own garden in the near future.

Dr. David Musnick, MD, IFMCP

David Musnick is a board-certified medical doctor who offers in-person and telemedicine care from the Functional Medicine of Idaho Eagle clinic (coming soon). Dr. Musnick offers Functional Medicine, Sports Medicine, Functional Immunology, and Primary Care for adults and teenagers. He specializes in sports medicine, internal medicine, frequency specific microcurrent (FSM), scars, homeopathy, prolotherapy, and low-level laser treatments. 

Dr. Musnick is interested in getting to the root of underlying causes and factors that affect healing, including diet, sleep, exercise, stress, GI health, brain region health, toxins, hormones, infections, and electromagnetic fields (EMF). In medical school, Dr. Musnick spent a year studying nutrition. He has always been interested in the complex interrelationships of different systems of the body. Taking on challenges in the past, he created new treatment programs to heal the brain after concussion, treat chronic pain, arthritis, and tough SIBO and IBS cases. Dr. Musnick wants to help his patients achieve the highest level of health, vitality and function. 

After his internal medicine residency in Seattle, Dr. Musnick completed a fellowship in sports medicine where he became interested in helping patients get back to optimal musculoskeletal health and eventually back to their favorite activities. He quickly learned that many areas of the body were interrelated and started learning more about nutrition, supplements, and other facets of functional medicine. Dr. Musnick has more than 24 years of experience in Functional Medicine and achieved a very high level of both experience and expertise with many health conditions. He is also the author of the book, Conditioning for Outdoor Fitness, and helped in writing textbook chapters on arthritis and concussions.

Dr. Musnick received his Doctorate of Medicine from the University of California, San Francisco. He is certified through the Institute for Functional Medicine as an IFMCP. He also studied in the French school of Homeopathy. He is uniquely rare in that he teaches Frequency Specific Microcurrent (FSM) and how to integrate it with functional medicine. 

In his spare time, Dr. Musnick enjoys hiking, nature photography, cooking healthy food, mountain biking, and skiing.

IFM Certified Practitioner

Aaron Dykstra, DNP, FNP-C

Aaron Dykstra is a board certified Family Nurse Practitioner with a Doctor of Nursing Practice degree. He offers pediatric primary care, including well-child checks and acute visits, in the Pediatric Department of the Functional Medicine of Idaho Meridian Wellness Center.

Functional and alternative therapies were a part of Aaron’s life from a young age, and he has implemented these principles into his conventional medicine practice throughout his career. Aaron has more than 8 years of experience in a variety of medical disciplines, including pediatrics, obstetrics, mental health, and nutrition. He has practiced in rural health clinics in California and Oregon. For the last 5 years, Aaron has had a passion for working with children and implementing positive change through the family unit. Aaron joined the Functional Medicine of Idaho Pediatric Team in 2021. His enthusiasm for educating children and parents about living a healthy lifestyle allows him to provide preventative and acute care for infants, children, and adolescents. 

Aaron obtained his Bachelor of Science in Nursing at Brigham Young University. He earned both his Master’s of Science in Nursing and Doctor of Nursing Practice through the University of Arizona. He has obtained a Family Herbalist and Family Nutritionist certifications through The School of Natural Healing by Dr. Christopher. He is currently working towards his certification with The Institute for Functional Medicine.

Outside of work, you will find Aaron spending time with his wife and 5 kids, mountain biking, running, or camping in the backyard. Aaron is a big fan of Master Chef and enjoys cooking.

Nadia Kravchuk, DNP, FNP-C

Nadia Kravchuk is a board certified Family Nurse Practitioner with a Doctor of Nursing Practice degree. She offers functional pediatric primary care, including well-child checks and acute visits, in the Pediatric Department of the Functional Medicine of Idaho Meridian Wellness Center.

Nadia and her family immigrated to the United States in 1989 where they first settled in Oregon and then moved to Idaho in 2001. Complementary medicine practices were embedded into her lifestyle at a young age, and she has implemented these principles into her conventional medicine practice throughout her career. She has more than 15 years experience in a variety of medical environments, including emergency room, intensive care unit, pediatrics, obstetrics and gynecology, family practice, and aesthetics.

Nadia joined Functional Medicine of Idaho so that she can combine functional principles with the foundations of conventional medicine to address the underlying causes of disease and promote optimal wellness. As an avid gardener, beekeeper, and sustainable living enthusiast, she understands the importance and role of optimizing nutrition, sleep, physical, spiritual, and emotional well-being. She has a passion for pediatric functional medicine and understands that early recognition and interventions can correct imbalances, prevent chronic illness, and improve overall outcomes for children.

Nadia obtained her Bachelor of Science in Nursing at Northwest Nazarene University. She earned both her Master’s of Science in Nursing and Doctor of Nursing Practice through Frontier Nursing University. In 2017, she was the recipient of the HCA Excellence in Nursing Award. She is currently working towards her certification with The Institute for Functional Medicine.

Outside of work, you will find Nadia working on her urban homestead, hiking, foraging, camping, snowboarding, and spending time with her husband and her dog, Wolfy. She is also fluent in both English and Russian.