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Where do I get plant-based Iron? Do I need to take B-12? What is DHA and do I need it?

Written by Ali Donahue
Where do I get plant-based Iron? Do I need to take B-12? What is DHA and do I need it?

Get your nutrition questions answered with Registered Dietitian Nutritionist and Licensed Dietitian, Addie Dulaney Majnaric 

Where do I get my iron on a plant-based diet? How much do I need?
Do I need to take B12?
What is DHA? Should I use a DHA supplement?

Where do I get Iron on a plant-based diet? How much do I need?

A: People are often concerned about their iron intake on a plant-based diet. It’s usually because they’ve heard all their lives that iron is the best source of meat.

The truth is, there are PLENTY of great sources of iron in plants! Beans, tofu, whole grains (like rolled oats or quinoa), leafy green vegetables, nuts, seeds, and dried fruit all contain adequate amounts of iron.

I recommend that beans or tofu are part of at least two meals a day, typically lunch and dinner. You also want to eat colorful meals, always including green from a green leafy vegetable (such as spinach, kale, Brussel sprouts, cabbage, collards).

To increase your body’s absorption of iron, pair iron-rich foods with sources of Vitamin C. These plants include strawberries, blueberries, citrus fruits, pineapple, kiwi, tomatoes, bell peppers of all colors, broccoli, sweet and white potatoes, and winter squash.

The amount of iron you need changes with age, gender, and life circumstances. These can include menstruation, blood loss (i.e., trauma or surgery), periods of rapid growth, and pregnancy.

The iron Recommended Dietary Allowance (RDA) for women is:

  • 15 mg/day for ages 14-18
  • 18 mg/day for ages 19-50
  • 8 mg for ages 51+

Pregnant women need 27 mg of iron per day, and breastfeeding women need about 10 milligrams per day.

The RDA for men is:

  • 11 mg/day for ages 14-18
  • 8 mg/day for ages 19+

The RDA for children is:

  • 11 mg/day for 7-12 months old
  • 7 mg/day for ages 1-3 years
  • 10 mg/day for ages 4-8
  • 8 mg/day for ages 9-13

It’s very much worth it to get these plants on your plate. Iron is an essential mineral for oxygen transportation through the bloodstream. We also need iron for cellular energy production and metabolism. In fact, iron is the most abundant mineral in the human body!

Q: What about B-12?

A: Vitamin B12 is a water-soluble vitamin that aids in the health of our nerve and blood cells. It also prevents megaloblastic anemia.

B12 is made by bacteria found in the soil. It is also found in the guts of animals. (Humans no longer produce B12 in the gut.) Because you are no longer eating meat, and we all wash the soil from our vegetables, I recommend that you take a B12 supplement

Our bodies require about 4-7 micrograms a day. However, we can only absorb about 1.5 micrograms every 4 to 6 hours. One recommendation is to take a 2500-microgram tablet under the tongue, once a week, as our bodies do passively diffuse about 1% of the tablet through our gut and into the bloodstream after the 1.5 microgram limit is reached.

If you prefer to take a small amount several times a week, you can take a 1,000-microgram sublingual tablet 3-4 times a week. Note that as B12 is a water-soluble vitamin, any excess amount is not stored, but filtered out through urine.

You can get some of your B12 from fortified foods such as nutritional yeast, some soy products, some plant milks, and some cereals. It is best to take a B12 supplement in addition to eating these foods, as there is no risk of over consumption.

Q: What is DHA? Should I use a DHA supplement?

A: DHA is an omega-3 fatty acid. It’s one of two “long-chain” omega-3s in our bodies (the other is called EPA).

We need DHA to improve heart health and vision and to reduce inflammation in the body. It also is crucial for the development of the brain during pregnancy and early child childhood.

Our bodies make DHA from “short-chain” omega-3 fatty acids that we eat. Our bodies do not make any omega-3s fatty acids on their own. We have to eat them in order to have them.

Plant-based foods high in omega-3 fatty acids are flax seed, chia seeds, and walnuts.

It’s recommended for adults to consume, per day, about 2-3 Tablespoons of ground flax seed, about 2 Tbsp of chia seeds, or ¼ cup walnuts to get appropriate amounts of omega-3 fatty acids. If you’re glucose-intolerant, flax seed may be the best choice for you. It is less fatty and less calorically dense than the other sources.

There are a few reasons to consider taking a DHA supplement.

  1. You’re unable to consume these foods regularly.
  2. You’re pregnant or breastfeeding.
  3. You don’t efficiently convert “short-chain” fatty acids to “long-chain” DHA. Your doctor can order a blood test to see how well you convert omega-3 fatty acids.

If any of these apply to you, one supplement option is 200 mg/day of DHA derived from marine algae. (This is where fish get their DHA.) When you avoid fish sources of DHA and EPA, you also avoid mercury, PCBs, dioxins, and other pollutant exposure. This is one reason it’s best to choose a vegan, non-contaminated source of DHA, such as supplements made with marine algae.

If you’re curious about DHA, then you’ve probably heard about another fatty acid — omega-6.

We need to eat both, but we need a lot more omega-3. And if we eat more omega-6 than omega-3, we actually become less efficient at converting omega-3s to DHA!

So how do you make sure you don’t over consume omega-6 fatty acids? First, you can ask your doctor to test your omega-3 to omega 6 ratio to see where your body is at.

Second, you can also stop eating animal products. This drops the amount of omega-6 fatty acids in your body. If you eat a no-oil, whole food, plant-based diet that is low in nuts and seeds, your ratio of omegas should be just fine.


Nutrition Answers with Addie Dulaney Majnaric, RDN


Your nutrition questions answered

Addie Dulaney Majnaric is a Registered Dietitian Nutritionist and Licensed Dietitian.
Each week Addie answers your nutrition questions.

How do I know if I'm getting enough protein?
Why am I so gassy?
Why am I pooping so much?

Q:  How do I know if I'm getting enough protein?

A: I get asked this often. The truth is, I have yet to see protein deficiency in anyone meeting their caloric requirements. A lot of people are actually exceeding their daily protein needs on a regular basis.

Most adults don’t need a high daily protein intake. The rule of thumb is 0.8 g/kg of your healthy, ideal body weight. Some studies show that even 0.8 g/kg may be too high, and that about 0.66 g/kg of your healthy, ideal body weight may be plenty of protein per day.

What does that look like? If your healthy body weight is 130 pounds (59.1 kg), you would need anywhere from 39 to 47 grams of protein per day. (Elite athletes, pregnant women, and those recovering from severe injury or surgery do need more.)

But you don’t need to open a nutrition tracker app at every meal to measure your protein. If you consume enough calories to maintain your healthy body weight, and you eat balanced, whole food plant-based meals, you are more than likely fine.

I recommend about 1 to 1.5 cups of beans a day to set the baseline for your protein, as well as your iron, B vitamin, calcium, and fiber intake. 

Whole grains, potatoes, nuts, seeds, lentils, and other legumes also have high amounts of protein. A lot of fruits and vegetables contribute to our daily protein intake, too. Here’s a quick rundown on just some of the many protein-rich plants.

1 cup of black beans = 14.2 g protein 

1 cup of chick peas = 11.6 g protein 

½ cup tofu = 10 g protein

½ cup oatmeal = 6 g protein 

1 baked potato = 5 g protein 

1 cup of broccoli = 2 g protein 

1 Tbsp of chia seeds = 3 g protein 

1 cup of blackberries = 1.4 g protein

What about eating more protein for muscular gain?

There really is no use. Your body can process only so much protein in a day, and the rest is excreted through your urine as nitrogen waste. In fact, consuming too much protein on a regular basis can damage your kidneys and increase inflammation in the body.

Stick to eating colorful meals, balanced with fruits, vegetables, whole grains, and beans, and you are well on your way to meeting all of your nutritional needs!

Q:  Why am I so gassy?

A: If you’re new to the plant-based life, chances are your energy has improved, maybe you’ve lost a little weight, your skin is glowing… life is good. Except for the gas!

Do not fear. This is completely normal, and it will settle down.

You have more gas because your intestines are waking up. Low fiber processed foods more or less put your intestines to sleep. As you eat more fiber-rich plants, healthy gut bacteria transitions to help you digest. New enzymes are activated, and the good gut bacteria in your colon creates gas as a by-product of this more alert digestion.

It takes time for your gut to adjust to change, but you can definitely help it along. Drink plenty of water. Eat consistent amounts of food at consistent times. Try cooked vegetables for some meals instead of all raw. Start with a smaller amount of beans at each meal.

Give it a few weeks, and soon your gut will actually function more optimally than ever before! Your digestive system LOVES fiber. it just needs time to get used to breaking down this new food profile.

Q:  Why am I pooping so much?

A: The short answer? You’re finally eating more fiber.

Our intestines love fiber. They function best when we eat 40 to 50 grams of fiber a day. But because Americans tend to eat high protein diets, heavy in animal products and dairy, most of us get only about 10 to 15 grams of fiber per day.

This means that many of us experience constipation or slowed bowel movements because we lack fiber. When you start eating a whole food plant-based diet, you finally get enough fiber to do one of its big jobs — forming poop! And cleaning out the buildup of decaying, processed, animal-product food that’s been sitting in your gut for a while!

However, that’s not all fiber does. Not at all. Fiber is truly one of the most important nutrients. It’s what we should focus on far more than protein, our society’s favorite nutrient obsession.

Fiber helps us in three main ways. First, it helps slow gastric emptying. This is the release of food from our stomach into our small intestine where the majority of nutrient absorption occurs. The slow-down makes our rate of nutrient absorption much more efficient.

Second, because fiber helps us absorb nutrients more efficiently, our blood glucose can stabilize. We don’t experience high energy spikes and big lows later on in the day.

Third, once the digestive process reaches the large intestine, fiber helps in the formation of stool.

Over a couple of weeks, your bowel movements will normalize. On average you’ll poop about 2-3 times per day. As a plant eater, you’ll typically have much more “regular” bowel movements and find it easier to go than people eating the Standard American Diet. Your colon will be much healthier, decreasing your risk of colon cancer. All because of the power of fiber! 


Nutrition questions?

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Addie Dulaney Majnaric is a Registered Dietitian Nutritionist and Licensed Dietitian.
Addie is available for private nutrition consultation/coaching in the city of Houston, TX as well as Southeastern Suburbs, predominately located in the Pearland, TX area. Specializing in lifestyle
disease reversal & prevention through the promotion of a plant based diet. She also works with
Dr. Jaimela J Dulaney's medical practice, based in Southwest Florida. Through the practice, she facilitates tele-health coaching programs, develops recipes for nutrition classes, manages the online education portal for the practice, and develops full encompassing health and wellness plans for members of the practice. With this platform, members have access to nutrition & health coaching from Addie as well as physician advisement - no matter their physical location.

Addie is a coauthor of the recently released cookbook, "Plant-based Wellness Cookbook: Three Generations of Cooking-the Doctor, the Dietitian, and the Diva"

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