Common Nutritional Deficiencies on a SIBO Diet (Part 1)

This weekend I led a workshop to discuss meal planning strategies and nutritional deficiencies for those following a SIBO diet.  I focused on the dietary deficiencies that I commonly see when trying to prepare nutritionally balanced meal plans following the SIBO Specific Food Guide.  This dietary approach created by Dr. Allison Siebecker combines the low FODMAP diet with the specific carbohydrate diet (SCD), along with her clinical experience.  While it can be an amazing tool for symptom reduction, I find that many SIBO sufferers are not aware of ways to protect against the nutritional deficiencies that commonly develop.

My goal in writing this post is to provide greater awareness and tangible solutions for preventing nutritional deficiencies.  While the particular nutrients discussed below are the most common deficiencies I see, the specific nutritional deficiencies that someone is likely to develop will depend on their unique circumstances.  Sounds like most things SIBO, right?  This is why it is so important to work with a practitioner who is skilled in SIBO nutrition and can analyze your diet, symptoms, and medical history and lead you to answers that work with your bio-individuality.

10 Common Nutritional Deficiencies on a SIBO Diet:

Let’s start out with a list of the most common nutritional deficiencies to look out for on a low FODMAP SCD diet (not in any particular order!):

1. Calcium
2. Vitamin D
3. Fiber
4. Folate
5. Vitamin B1
6. Iron
7. Zinc
8. Potassium
9. Carbohydrates
10. Calories

SIBO-Specific Superfoods For Combating Nutritional Deficiencies

It is of course important to remember that if you react to a food that appears on this list, it is not be a superfood for you!  Finding other foods that provide similar nutrients will help you find your individualized superfoods.

• Bone-in canned fish (such as sardines, salmon)
• Cod liver oil
• Oysters
• Eggs
• Leafy green vegetables (spinach, kale, turnip greens, beet greens, collard greens, etc)
• Banana
• Spaghetti squash
• Strawberries
• Bell pepper
• Bok choy
• Celery root (celeriac)
• Parsley
• Sunflower seeds
• Pumpkin seeds
• Sesame seeds (or tahini)
• Almonds (or almond butter)
• Peanuts (or peanut butter)
• Cumin
• Turmeric

1) Calcium

Calcium is best known for its role in helping maintain strong bones and teeth.  It is also important for nerves, muscles, cell signaling, vasodilation, and hormone secretion.  Additionally, research suggests that it may play a role in maintaining healthy blood pressure, preventing colon cancer, and reducing the risk of pre-eclampsia in pregnancy.

Most of us know that dairy products are often discussed hand-in-hand with calcium.  Many also know that there is controversy around whether dairy products are actually a bio-available source of calcium, but we are NOT going to get into that here.  What we are going to discuss is the fact that it can be challenging to meet the recommended dietary allowance (RDA) for calcium on a low FODMAP diet, particularly one that does not include dairy products.

Some of the most rich non-dairy sources of calcium include tofu, sardines/salmon (bone-in), sesame seeds, leafy greens, cinnamon, oranges, and fortified non-dairy milks.  On a strict SIBO Specific Diet, tofu and fortified non-dairy milks may be off the list.

Now, let’s get into the numbers.  The RDA for calcium for a middle-aged adult is 1,000 mg.  Let’s take a look at the quantity of SIBO specific items that would need to be consumed in a single day to obtain this level.  Then your job is to compare it to your reality.  Here we go:

• 1 tin bone-in sardines (apx. 5 oz) = 500 mg calcium
• 2 tablespoons sesame seeds = 176 mg calcium
• 10 (not baby) spinach leaves = 100 mg calcium
• 1 cup cooked kale = 94 mg calcium
• 1 navel orange = 60 mg calcium
• 1/2 cup raw bok choy = 37 mg calcium
• 1 teaspoon cinnamon = 26 mg calcium
• TOTAL = 993 mg calcium (just under the RDA for middle-aged adults)

In my opinion, this may be feasible for a day or two, but as you may see, the bone-in fish is a significant contributor to meeting the RDA.  I don’t know about you, but I just can’t imagine eating this amount of canned bone-in fish every single day.  Bleh.  Food is supposed to be enjoyable, not repetitive!

When individuals are recommended dairy-free diets, they may also be placed on calcium supplements.  Unfortunately, calcium supplementation can come with the unwanted side effects of constipation, gas, and bloating.  Wait, isn’t this what we were trying to avoid in the first place by eliminating dairy and FODMAPs? Yes!

A calcium supplement that has worked well for me in regard to preventing the aforementioned side effects is coral calcium.  The one that I use contains magnesium oxide to help reduce any constipation that can be caused by calcium supplementation.  If you are concerned about your calcium intake, talk to your doctor about whether coral calcium or another form of calcium (such as citrate) may be a good option for you and about their recommendation for a high-quality product.

2) Vitamin D

Vitamin D is another important player in maintaining healthy bones and teeth.  Adequate vitamin D levels are also important for allowing us to absorb calcium in the small intestine.

The cool thing about vitamin D is that it can be synthesized by our bodies when we are exposed to UV rays from the sun.  Unfortunately, living far from the equator, using sunscreen, and spending lots of time indoors limits our ability to synthesize adequate vitamin D to meet our needs.

The current RDA for a middle-aged adult is 600 IU per day.  The major dietary contributors include fortified dairy products, fortified juices, fortified cereals, fish (salmon, sardines, tuna), and eggs.  Non-animal sources of vitamin D are very limited.

Here’s some examples of the amount of vitamin D in fish and egg sources:

• 3.5 ounces cooked sockeye salmon = 522 IU vitamin D
• 2 large eggs = 82 IU vitamin D
• Total = 604 IU vitamin D (yay, we made it to the RDA)

Again, we see that it is absolutely possible to make it to the RDA for this nutrient, but it may not be feasible to meet it every day due to the limited number of items containing vitamin D.

Many individuals going to naturopaths, other alternative medicine practitioners, or even conventionally-trained physicians are prescribed vitamin D supplements.  Vitamin D levels can be tested in the blood and supplemented accordingly with the guidance of a practitioner.  Cod liver oil may be a viable option for supplementing with vitamin D in a way that more closely resembles food.  I find that it is important to retest levels after a period of supplementation with vitamin D as individuals greatly differ in their ability to absorb and utilize this nutrient.

3) Fiber

Fiber has gotten sort of a bad rap in the SIBO community.  It seems that conventional gastroenterologists jump to fiber as the remedy for diarrhea/constipation while many SIBO practitioners act like its the enemy.  The importance here is finding the right amount for your body, in the right form, at the right time.  I know, it sounds complicated, but it doesn’t have to be.

Fiber is important for blood sugar regulation, aiding in removal of toxins from the body, producing short-chain fatty acids (SCFAs) that keep the colon healthy, and it is believed to play a role in cardiovascular health.  It can also help keep the bowels regular when used appropriately.

Both low FODMAP diets and SCD diets run the risk of containing inadequate levels of fiber (intentionally).  This is because they restrict certain carbohydrates and fiber happens to be a form of carbohydrate.  Diets that do not contain legumes, grains, and high fiber/high FODMAP vegetables, make it more challenging to obtain the RDA for fiber.

The current RDA for fiber for a middle-aged female is 25 grams and for a middle-aged male is 38 grams.  Here are some of the higher fiber foods to help meet the RDA while following a SIBO diet:

• 1 medium banana = 3.1 g fiber
• 1 cup (cooked) spaghetti squash = 2.2 g fiber
• 1 kiwi = 2.1 g fiber
• 10 almonds = 2.0 g fiber
• 1 cup raw collard greens = 1.4 g fiber
• 1/2 cup (cooked) broccoli = 1.3 g fiber
• 10 raspberries = 1.2 g fiber
• Total = 13.3 g fiber (that’s only 1/2 the RDA for middle-aged women!)

I think the take away message for fiber is that when following a SIBO diet, it is very important to make sure it is rich in fruits and vegetables in order to obtain the RDA for fiber.  Even so, it may still be difficult to meet the recommendations and a less strict diet (such as including whole grains or more FODMAPs) may be appropriate for some people.

4) Folate

When I think of folate deficiency, I think of neural tube defects.  While the equation is not always as simple as folate in, folate out (I’m talking MTHFR here!), obtaining a baseline level of folate from food is an important factor to consider.  For women who may become pregnant, folate is a very important nutrient to obtain in adequate amounts as it is vital in the first 3 weeks after conception for preventing neural tube defects.  However, folate also plays vital roles in the functioning of our DNA, in amino acid metabolism, in detoxification, in neurotransmitter production, and in the production of blood cells.

Folate is commonly found in foods such as leafy green vegetables, legumes, and some fruits.  Individuals following a standard american diet (SAD) that is void of many vegetables are likely to be obtaining the majority of this nutrient in the form of fortified grains containing folic acid.  Therefore, when fortified refined grains are eliminated from the diet in favor of a SIBO diet, a risk of deficiency arises.

The RDA for middle-aged adults is 400 mcg.  Here’s one way to meet the RDA with SIBO specific foods:

• 15 (not baby) spinach leaves = 285 mcg folate
• 1 cup shredded romaine lettuce = 64 mcg folate
• 1 cup red bell pepper strips = 22 mcg folate
• 1/2 cup sliced strawberries = 20 mcg folate
• 3 cherry tomatoes = 9 mcg folate
• Total = 400 mcg folate (exactly the RDA!)

Some other food sources of folate to play around with include parsley, broccoli, cabbage, zucchini, and green beans.  The takeaway with folate is that it is not difficult to get as long as you are including leafy green vegetables and a variety of other fruits and vegetables in your SIBO diet.  It is difficult, however, if you skimp out on the greens.

5) Vitamin B1

Vitamin B1, also called thiamin, is involved in the metabolism of carbs, fats, and proteins.  A deficiency of this vitamin can impact the cardiovascular, nervous, gastrointestinal, and muscular systems.  A deficiency has also been associated with Alzheimer’s disease, congestive heart failure, and some cancers.

Rich sources of vitamin B1 include whole grains, fortified refined grains, yeast, green peas, and pork.  These major sources may be limited for some people following a SIBO diet.  However, with a little close attention, obtaining adequate vitamin B1 is completely achievable.

The RDA for vitamin B1 for a middle-aged male is 1.2 mg and for a middle-aged female is 1.1 mg.  Here’s one way to achieve adequate intake for a day:

• 3 oz bone-in pork loin chop = 0.51 mg B1
• 2 tablespoons sesame seeds = 0.14 mg B1
• 15 (not baby) spinach leaves = 0.12 mg B1
• 10 pecan halves = 0.09 mg B1
• 1 navel orange = 0.09 mg B1
• 1 teaspoon ground flax seeds = 0.06 mg B1
• 2 teaspoons sunflower seeds = 0.04 mg B1
• 2 cups cubed eggplant = 0.06 mg B1
• Total = 1.1 mg vitamin B1 (meets middle-age female RDA)

That was a lot of items I had to come up with in order to achieve the recommendations for B1 for a day.  And much of the daily supply came from pork.  So for those who do not eat pork, you may need to be more mindful about getting in enough of this nutrient.  For those who can include some grains and higher FODMAPs, 1 cup of green peas supplies a whopping 0.41 mg B1 and 1 cup brown rice supplies .19 mg B1.  Other items to include in your diet if you are trying to increase vitamin B1 include cantaloupe, eggs, nutritional yeast (hasn’t been tested for FODMAP content), fish, acorn squash, and macadamia nuts.

6) Iron

A staggering 12 percent of women in the US ages 12-49 have iron deficiency.  Iron is important for transporting oxygen around the body and it is involved in certain energy formation reactions.  Iron deficiency can be seen by examining blood work, but several symptoms can provide clues for the need for testing.  Some of these symptoms include weakness, fatigue, hair loss, pale appearance, reduced attention span, and frequent infections.

There are many factors besides dietary intake that play into iron deficiency.  A few of these include use of acid-blocking drugs like proton pump inhibitors (PPIs), low stomach acid, and excessive blood loss (such as with heavy periods).  Another issue for some people is the presence of bacterial overgrowth in which the bacteria consume the iron instead of letting it get absorbed by the human.

But today, we are just going to talk about the simple in and out.  Iron needs vary greatly between different life stages.  If you do a quick google search for the RDA for iron, you will find the value that applies to your age, gender, and pregnancy status.  For simplicity sake, we will see how we can obtain the RDA for non-pregnant women ages 19-50.  For this group, the RDA is 18 mg/day. Let’s take a closer look at one way to obtain this:

• 4 oz. grass-fed ground beef = 2.25 mg iron (higher bioavailability)
• 15 (not baby) spinach leaves = 4.05 mg iron (lower bioavailability)
• 2 teaspoons turmeric = 3.30 mg iron (lower bioavailability)
• 2 teaspoons cumin = 2.78 mg iron (lower bioavailability)
• 2 tablespoons sesame seeds = 2.62 mg iron (lower bioavailability)
• 1/2 cup parsley = 1.86 mg iron (lower bioavailability)
• 1/2 cup bok choy = 0.28 mg iron (lower bioavailability)
• 2 tablespoons pumpkin seeds = 0.27 mg iron (lower bioavailability)
• Total = 17.41 mg iron (alright, we almost made it to the RDA for women ages 19-50)

One of the main groups I thought about when deciding to include iron on the SIBO diet common nutritional deficiencies list was those who are following a pescatarian, vegetarian, or vegan diet as well.  These diets can make it exceptionally difficult to obtain adequate nutrition, variety, and sanity on a SIBO diet.  But even without these extra dietary restrictions, it can be hard to obtain adequate iron intake.

You may have also noticed that I indicated “lower bio-availability” or “higher bio-availability” next to the various iron-containing foods.  This is because the form of iron found in animal products is more bio-available to our bodies than the form found in plant foods.  One way to increase the amount of iron that is absorbed from plant foods is to add vitamin C.  So sprinkle some lemon juice on your spinach- it’s tasty and nutritious!

7) Zinc

The next nutritional deficiency we will be discussing is zinc deficiency.  Similarly to iron deficiency, it is an issue that is more concerning to me when individuals are following a SIBO diet, but also a vegetarian or vegan diet.  

Zinc, which is commonly found in seafood, red meat, nuts, and legumes is an important nutrient for growth, the immune system, the neurological system, and a variety of other functions.  Deficiency commonly manifests with symptoms such as increased susceptibility to infections, diminished taste perception, delayed sexual maturation, delayed wound healing, night blindness, and behavioral issues.

The current RDA for middle-aged males is higher than that for females, at 11 mg and 8 mg, respectively.  In order to obtain the RDA for middle-aged males, the following could be consumed within one day:

• 1 raw oyster = 10 mg zinc
• 1 tablespoons almond butter = 0.53 mg zinc
• 2 tablespoons peanut butter = 0.80 mg zinc
• Total = 11.33 mg zinc (meets the RDA for middle-aged males)

Since many people do not eat oysters on a daily basis, here’s a look at some other sources of zinc:

• 3 ounces grass-fed ground beef = 3.87 mg zinc
• 1 cup chopped chicken breast = 1.36 mg zinc

Limiting legumes and certain vegetables (such as broccoli) makes it more difficult to obtain adequate zinc.  But throw in a couple oysters or other forms of seafood every once in awhile, and there should be less concern.

8) Potassium

Potassium is an electrolyte found in a variety of fruits, vegetables, nuts, seeds, and legumes.  Adequate potassium intake may help prevent high blood pressure, stroke, osteoporosis, and kidney stones.

Potential signs of potassium deficiency include fatigue, muscle cramps, muscle weakness, and potentially intestinal paralysis.  Slow intestinal function (intestinal paralysis) can lead to SIBO symptoms such as bloating, constipation, and abdominal pain.  This is one of the primary reasons it is important to make sure to obtain adequate potassium while on a SIBO diet.  Otherwise, it may be difficult to figure out what is causing your digestive symptoms.

Supplementation with potassium should be carefully monitored by a healthcare practitioner as excessive supplementation can have serious consequences.  

A safer way to obtain potassium is to get it from foods.  Below is an example of foods to help a middle-aged adult meet the RDA of 4,700 mg:

• 15 (not baby) spinach leaves = 840 mg potassium
• 1 cup celeriac (celery root) = 468 mg potassium
• 1 banana = 422 mg potassium
• 3 ounces canned salmon = 280 mg potassium
• 1 tomato = 235 mg potassium
• 1 navel orange = 232 mg potassium
• 2 cups raw kale = 158 mg potassium
• ¼ cup coconut water = 150 mg potassium
• 1 tablespoon almond butter = 120 mg potassium
• 1 cup spaghetti squash = 109 mg potassium
• 2 tablespoons sesame seeds = 84 mg potassium
• 2 teaspoons sunflower seeds = 45 mg potassium
• Total = 3,143 mg potassium (That’s only about ⅔ of the way to the RDA!! But I think you get the point.)

For those who tolerate potatoes and sweet potatoes, these two items can provide a good quantity of potassium to help someone reach the RDA.  Other foods rich in potassium include avocados, yogurt, mushrooms, and beans.

One factor that may play into individual variation in needs for potassium is the amount of sodium consumed.  While those with diets higher in sodium may see the effects of potassium deficiency sooner, those who do not consume excessive amounts of sodium may not experience potassium deficiency to as great of a degree.

9 & 10) Carbohydrates/Calories

Calorie and carbohydrate deficiencies are two of the most common nutritional issues that I see when individuals are prescribed SIBO diets without being given much direction.  They are also some of the most concerning. This is why I will be dedicating an entire post to discussing the topic in detail.  Stay tuned and be sure to subscribe to receive updates!