The 13 Rules of the Coimbra Protocol Diet

When you begin your Coimbra protocol, you’ll receive several dietary guidelines.

These guidelines are in place for two reasons: to increase the protocol safety and to improve your chances of a successful outcome – a significant improvement in your symptoms.

In this article, you’ll learn all the known guidelines reported by Dr. Coimbra patients.

As an additional note, please bear in mind that due to the experimental nature of high-dose vitamin D protocols, your Doctor may decide to modify some of these rules to better suit his therapeutic goals.

How can you avoid becoming overwhelmed by all these rules?

You have to understand the why behind each dietary recommendation.

This will allow you to adapt each dietary guideline to your own circumstances while preventing you from becoming paralyzed by any information overload.

Once you realize the why, the how becomes much simpler.

That’s why these guidelines have been divided into 13 more manageable rules.

Warning: This is an in-depth article.

If you are in a hurry, though, I’ve prepared this nice infographic that sums up these rules for you.

Feel free to share as long as you link back to this page.

Rule 1: Stop eating and drinking all milk and dairy products

Vitamin D enhances your ability to absorb calcium from food.

At first glance, this may sound like a great thing, but it isn’t.

In fact, it’s the main reason why vitamin D therapy can become dangerous.

Why?

Because, even though calcium is vital for your health, too much of this mineral can cause all sort of health issues.

In extreme cases, high calcium blood levels can even lead to mental confusion, coma, and even death.

On top of that, as your kidneys attempt to clean up any calcium in excess from your blood, you may end up with a high calcium concentration inside your kidneys.

This comes with its own additional set of complications.

That’s why protocol Doctors are so paramount in letting you know, in no uncertain terms, that calcium-rich foods can’t be consumed while you are on the protocol. Period.

This is a nonnegotiable rule.

Moreover, vitamin D also stimulates the natural process of bone resorption.

That’s when a group of bone cells, the osteoclasts, erode away bone tissue, causing calcium and phosphorus to be released from the bone, back into the blood – hence the term resorption, because the blood is reabsorbing the building materials it once brought to help build up that bone.

As you can see, this will further disrupt your blood mineral levels.

For this reason, calcium blood and urine levels are one of the main concerns of your Coimbra protocol Doctor.

Of course, not all dairy is calcium rich.

However, to simplify things and guarantee that no high-calcium dairy food is mistakenly ingested, a no-milk, no-dairy diet is prescribed.

This doesn’t include bread, cakes or cookies that were prepared with milk since the calcium-content on these foods would be much lower than a full glass of milk or a slice of cheese.

More about this on rule 12.

Rule 2: Stop drinking any calcium-fortified vegetable milks, green smoothies or too much Orange Juice

The second rule is unsurprising.

If the goal is to reduce calcium intake anything that has been fortified with it must be cut off too.

This would include any vegetable “milks” such as almond, rice, soy, or coconut milk, as long as they’ve been fortified with calcium.

How can you tell if a vegetable milk has been fortified?

Fortifying a drink with calcium increases production costs.

Manufacturers do it because calcium is regarded as a good thing by their target consumers.

How so?

Many of the people who buy these items do so because they are looking for a dairy-free alternative to milk. By fortifying their vegetable drinks with calcium, manufacturers are catering to this need of theirs.

For this reason, you can expect that they’ll put a big, hard to miss, label on their packet letting you know their drink has been fortified.

And that’s how you can tell.

Most brands won’t go the extra mile and add calcium to their product and then fail to tell their target audience all about it. It just wouldn’t make sense from a marketing perspective.

Then, if you are holding a packet of rice milk and those eye-catching labels are nowhere to be seen, you are most likely to be holding something you can safely drink.

To be 100% sure, though, turn it around and look for any mention of calcium in the list of ingredients.

If there’s none, it’s safe to drink.

What about green smoothies and orange juice?

Most smoothies have the same base ingredient: spinach.

Do you think spinach is a calcium-rich food?

Most people do. But, is it?

When I compiled the list of the richest calcium sources spinach hardly found its way in.

With just 99 mg of calcium per 100 grams, spinach was the 114^th, and last, item on the list.

In fact, I kind of extended the list until I got to spinach just so readers wouldn’t think that I had forgotten about it when preparing the list.

Why, then, are Coimbra protocol Doctors advising against green smoothies?

After all, at 30 grams, a cup of spinach contains less than 30 mg of calcium – about as much as one large egg.

That’s not much.

Then, why the ban on green smoothies?

It might be because they thought spinach was high in calcium just like most people think – that’s a possibility.

However, there’s a better explanation.

Spinach is high in oxalates.

And, when you mix calcium, or phosphorous, with oxalate you can get kidney stones. (1)

Now, if you are taking a large amount of vitamin D, you’ll have a considerable amount of calcium and phosphorous passing through your kidneys most of the time.

As such, adding too much oxalate to your diet would be a terrible idea.

That's the same reason why you should also avoid vitamin C supplements: they break down into oxalates.

Then, why not simply forbid all spinach intake?

Probably because a regular individual will eat spinach every other day, while a person who does green smoothies, will tend to do so more regularly.

As you can see, once again, there might be a tendency from your Coimbra protocol Doctor to oversimplify your diet plan by simply banning a whole group of items.

However, by understanding why they are advising you in that manner, you’ll be better equipped to make more thoughtful decisions.

Rule 3: Stop eating nuts and any dried fruits containing seeds

Your protocol Doctor may hand you a list forbidding you from eating any foods such as:

But why?

For one, there’s the oxalate content, again.

Yet, not all of these foods contain a significant amount of oxalate.

Some, like pistachio, are low sources of oxalate.

Could it be because of their calcium content?

Almonds and hazelnuts are high in calcium. With 268 milligrams and 250 milligrams, respectively, per 100 grams – according to the USDA.

Yet, once again, this doesn’t apply to all nuts. Cashews, for example, have just 37 milligrams.

What about phosphorous?

Even though vitamin D toxicity is synonymous with hypercalcemia (very high blood calcium levels) and hypercalciuria (very high urine calcium levels), too much vitamin D can also raise your phosphorous levels through the same mechanisms.

Since nuts and seeds can have a good phosphorus content, it makes sense protocol Doctors would want you to be careful about them too.

Yet, rice is one of the highest phosphorous containing foods and it isn’t banned nor restricted during the protocol.

What gives, then?

Based on all we’ve considered, I think we can take an educated guess about the reason why nuts and dried foods containing seeds are banned:

Even though not all of them are high sources of calcium, oxalates or even phosphorus, they do tend to contain these 3 elements in significant amounts.

Keeping up with the tendency to simplify what you should and shouldn’t eat by food groups, it’s easier for the patient to just keep a mental note that nuts are out, instead of having them remember specifics details about a lot of different foods.

For example, that he should be careful about hazelnuts because of the high calcium levels, of cashews because they have a high oxalate content despite being low in calcium and of other nuts because they might be high in phosphorus.

Rule 4: Avoid eating too much açai

The Coimbra Protocol was born in Brazil.

For this reason, it contains some dietary guidelines adapted to the Brazilian culture.

Açai, a small dark blue berry, is a popular fruit over there.

As you may be correctly guessing, it is also a good source of calcium.

Finding exactly how much calcium is in 100 grams of açai berries proved more difficult than expected, though.

That’s because the entry in the USDA database has “0 mg.” This means they haven’t, as of January 2019, added all the details about açai berries to their database.

However, there’s an article claiming açai can contain up to 309 milligrams of calcium per 100 grams – but they didn’t provide their sources, so I can’t take their word for it.

What I did find, was a research paper stating that “açai pulp is rich in essential minerals,” including calcium. (2)

Hence, the recommendation to avoid eating too much of it makes perfect sense.

Rule 5: Avoid any dishes from Lebanese cuisine made with sesame seeds paste

Here the main culprits are:

Why?

Because tahini is a condiment made from sesame seeds and sesame seeds contain a lot of calcium.

For this reason, tahini is out.

What about hummus?

Hummus is “a paste of pureed chickpeas usually mixed with sesame oil or sesame paste and eaten as a dip or sandwich spread.” (3)

Sesame seeds again.

As you may be guessing by now, baba ghanoush also has sesame seeds as one of its ingredients – in the form of tahini, to be exact.

According to the Merriam Webster dictionary, it is “an appetizer or spread made chiefly of eggplant, tahini, garlic, olive oil, and lemon.” (4)

Just how much calcium do sesame seeds contain?

They are in the 8^th position of our list of 114 calcium-rich foods.

They have 975 mg of calcium per 100 grams – that’s more than most cheeses.

What about tahini?

The calcium contents of tahini may vary, but according to the data published by the USDA, tahini made from roasted and toasted kernels, the most common type, has 426 milligrams of calcium per 100 grams.

For this reason, as healthy as these Lebanese dishes may be, they are too high in calcium to be safely eaten while on the Coimbra Protocol.

You must either avoid all such dishes or cook them yourself using a low-calcium tahini alternative.

Rule 6: Don’t eat Any anchovies, or sardines, with their fishbones

Just like eggshells, fishbones are tremendous sources of calcium.

But unlike eggshells, which I’m sure you’d be hard-pressed to consume, fishbones can sneak into your gut when you’re eating canned anchovies or sardines.

On top of them, they are also excellent sources of phosphorous.

It’s also worth mentioning that here in Portugal, for example, it is common to fry small mackerel fish and eat it whole – fishbones et all. We called them fried jaquinzinhos. I guess it’s too troublesome to remove the small bones from the fish. But if you are taking high doses of vitamin D, you must do it.

Rule 7: Stop consuming carbonated beverages

When you are taking a supplement that can raise your calcium levels, your kidneys become one of your main lines of defense.

They are key to performing two vital steps:

Excreting any minerals in excess.

Activating vitamin D.

To put things in even more perspective, unhealthy kidneys may even prevent you from continuing with the protocol.

Unfortunately, this might turn in an uphill battle, has many of the drugs used to minimize the symptoms of autoimmune disorders, like cortisone and most painkillers, are hard on the kidneys and you may be instructed to continue to take them while on the protocol.

This means you must do all you can to keep your kidneys healthy.

That’s the whole reason for the ban on carbonated drinks. They are not healthy for your urinary tract and some of them, like cola beverages, are linked to kidney stone formation. (5)

Avoid cola like the plague, our kidneys are worth more than the sugar-induced rush cola causes us.

What about coffee?

Rule 8: Avoid drinking too much coffee

Unlike carbonated beverages, which have no health value, coffee contains hundreds of substances, some of which seem to do us good. (6)

What would be considered a moderate amount of coffee, then?

In a recent paper reviewing the effects on coffee on human health, Doctor Karen Nieber, from the University of Leipzig, Germany, stated:

According to this researcher, 3 to 4 cups of coffee a day is a moderate amount.

I’ve once heard a person bragging about having drunk 19 (nineteen) cups of coffee in a single day. That’s certainly not a moderate amount.

However, when you are taking a large amount of vitamin D things are not always as linear as this.

For example, a study from 2001, published in The American Journal of Clinical Nutrition (8) had the following enlightening title: “Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes.”

When you are on the protocol, besides these dietary guidelines, you’ll also receive instructions to keep yourself active, at least going out for a walk every day. Why?

Because doing so stimulates your bones to reabsorb calcium from the blood.

Why is this so important?

Because, by overstimulating osteoclast activity, high doses of vitamin D promote bone decalcification.

Hence, if caffeine has the potential to further increase this bone loss, you must be extra careful about your coffee intake.

How much more careful?

As the study conclusion states:

300 milligrams/day is lower than the 400 milligrams/day safety ceiling purposed by Dr. Nieber.

Also, there’s another important aspect worth pointing out.

Depending on their vitamin D receptor genotype, some women were especially vulnerable to the “deleterious effect of caffeine on bone.”

Do you know what’s your vitamin D receptor genotype?

If you are like me and most everyone else, chances are, you don’t. What if you have the tt genetic variant of the vitamin D receptor?

Could that mean that you’d be more vulnerable to the harmful effects of caffeine over your bones?

This is something worth considering, even if you are not an elderly postmenopausal woman – and especially so if you are.

Therefore, be sure to keep your caffeine intake in check, never exceeding the 300 milligrams/day.

Rule 9: Avoid eating too many bananas, star fruit, and the fruits from the Annonaceae family

Why should you avoid eating too many bananas while on the protocol?

Bananas have 5 mg of calcium, and 22 mg of phosphorus, per 100 grams. Negligible amounts. The same being true for their oxalate content.

Why then, does Dr. Coimbra advise against eating too many bananas?

Due to their high potassium content, bananas are unadvisable to someone undergoing some forms of dialysis, as they may promote a potentially fatal potassium buildup on their blood.

When a person has functioning kidneys, any excessive potassium is promptly excreted. But, if you are reliant on the dialysis machine to remove any minerals in excess, you must be careful about taking too much potassium. Why?

Because contrary to calcium, sodium or phosphorus, which give you many warning signs, and enough time to do something about their build up, a sudden rise in potassium will simply stop your heart.

That’s why most patients on dialysis are told to avoid bananas.

However, unless you are undergoing dialysis, foods high in potassium are actually good for you.

Why then, did Dr. Coimbra advise against the consumption of too many bananas?

It may not be because of the bananas themselves, but rather the way they are grown.

Bananas are one of the most pesticide-intensive crops. One of the pesticides used being chlorpyrifos, which is a potent neurotoxicant. (9)

However, it’s worth noting that these chemicals are mostly present on the banana peel, being undetectable in the fruit itself.

Yet, since a good number of Dr. Coimbra patients suffer from neurodegenerative autoimmune diseases, like multiple sclerosis, it makes sense that he would worry about them eating too much of a fruit known to be ridden with a neurotoxicant substance – even if this is true only with respect to the banana peel and not to the fruit itself.

If this is the only reason for the soft ban on banana consumption, you’d be safe eating organically grown bananas, though.

Why should you be careful about star fruit?

Star fruit, known in Brazil as “carambola,” is a tropical fruit known to be potentially harmful to your kidneys.

Both star fruit and its juice have a high oxalate concentration. (10)

Although someone with healthy kidney function should be safe consuming small amounts of carambola, since their kidneys would be able to clear the oxalates, it’s worth noting that even a dose as little as 25 ml of star fruit juice has been linked to nephrotoxicity – a severe impairment of kidney function. (11)

Furthermore, according to a group of investigators from Sri Lanka:

Also, according to the National Kidney Foundation: “The substances found in starfruit can affect the brain and cause neurological disorders.” (13)

At his point, you might be wondering why anyone would want to eat star fruit.

In case you are, there are two factors you must take into consideration:

When we take all these factors into account, Dr. Coimbra’s recommendation seems balanced: avoid eating star fruit in excess – unless, of course, if you have kidney problems.

What about the annonaceae family of fruits?

You may think you’ve never heard to talk about this family of fruits before, but does the name “graviola” ring any bell?

Graviola is just one of the elements of this large family of fruits, though.

According to Wikipedia, members of the annonaceae family include custard apple, cherimoya, soursop, guanabana, graviola, sweetsop, ilama, soncoya, atemoya, and biriba – a kind of honorary annonaceae. (15)

To complicate things, some of these names can sometimes end up being used interchangeably in everyday conversations.

But you don’t need to memorize any of them.

If you happen to live in Portugal, Brazil, or any other country where regular consumption of any of these fruits is common, all you need to keep in mind is that you must be careful about eating them regularly.

Why?

Because they contain chemicals known to be neurotoxic. (16)

Of special interest to researchers is annonacin, which can cross the blood-brain barrier and damage nerve cells. (17) This substance is even though to be the cause of an atypical kind of Parkinson’s Disease seen especially in Guadeloupe. (18)

Will you get Parkinson’s from eating an annona? No. But if you are doing the Coimbra protocol, chances are you have a degenerative disease, maybe even one affecting your brain and nerves.

That’s why you should be especially careful about your consumption of these types of foods.

It’s no longer just about calcium and vitamin D. You also want to avoid eating something known to hinder your progress.

Knowing this will help you understand the next rule.

Rule 10: Restrict your meat intake

A Coimbra protocol doctor may ask you to limit your meat consumption.

In fact, you may be advised to try and become as close to an ovo-vegetarian-who-also-eats-fish as possible.

Why?

Because of a group of substances called heterocyclic amines, or HCAs.

What are heterocyclic amines?

If you look up “heterocyclic amine” in the National Cancer Institute Dictionary of Cancer Terms you’ll find the following definition:

This sums up it pretty well.

You might notice that both meat and fish are listed, yet, the protocol diet guidelines call attention to meat (including poultry) only, not fish.

Why?

Because the idea is for you to reduce your consumption of HCAs, not to restrict them completely.

Limiting meat instead of fish makes a lot of sense when you consider Brazilian culture.

In Brazil, barbecued meat is cooked over a longer period of time than in the US. This process is called a churrasco and is incredibly popular. (20)

Since cooking muscle meat at high temperatures for a long period of time is one of the key components of HCAs formation, by limiting his meat intake, and, by extension, his churrasco meals, a person will reduce his HCAs intake.

Heterocyclic amines aren’t the only carcinogens present in meat but are the ones focused on by Dr. Coimbra.

Rule 11: Drink at least 2.5 liters (2.64 quarts) of fluids every day

This is one of the most well-known rules of the protocol. Please don’t ignore it.

As you know, during the protocol, your kidneys will be working hard to keep your mineral levels in check.

This means there’ll be a significant amount of calcium passing through the tiny tubes that make up your urinary system.

Then, if you don’t drink enough liquids, this calcium won’t be diluted adequately, and you won’t be as protected against the formation of kidney stones as you could. (21)

Do 2.5 liters sound like too much?

Remember this includes all liquid beverages like juices and teas, not just water.

As a friendly reminder, keep in mind that some teas can contain high amounts of oxalates, especially if you brew them for too long (22) and, as such, can contribute to stone formation, while others can help prevent these very stones from forming (23), and even, in some circumstances, make it easier for your body to remove them (24) – so, choose your teas wisely.

Rule 12: Remember that you can eat foods that were prepared with milk, such as bread, cookies, cakes and mashed potatoes – as long as you’re sure that they haven’t been fortified with calcium

If you feel confused about this rule, that’s understandable.

Rules number 1 and 2 made it clear that dairy and fortified products were out.

Then, how could foods prepared with milk be in?

You need to look at it from the perspective of someone who is following all the protocol guidelines.

Such a person will be cutting out more than dairy and fortified foods; he’ll also be cutting all nuts, drinking a lot of fluids, and, all the while, be supplementing with several important vitamin D co-factors.

Taking all this into account, a Coimbra protocol Doctor feels comfortable about letting cookies and cakes in – as long as they haven’t been fortified with calcium.

How much calcium is in cakes and cookies?

According to the USDA, a commercially prepared cheesecake has 51 milligrams of calcium per 100 grams. That’s 64 milligrams of calcium in a serving – assuming 125 grams for the serving size.

As a comparison, one large orange (184 grams) has 74 milligrams of calcium.

From this perspective, a slice of cheesecake could be considered a low calcium food.

Similarly, butter cookies have 29 mg of calcium per 100 grams. That’s 1.4 milligrams of calcium per cookie – assuming each cookie weights 5 grams.

Also, according to the same source, a cup of mashed potatoes (210 grams) made with milk and butter contains 73.5 milligrams of calcium.

Yet, before adding these items to your diet, there are some factors you need to take into consideration.

First of all, these values will vary depending on how much milk and dairy was used by the person preparing the recipe.

Also, calcium carbonate may have been added to the flour – this is mandatory in the United Kingdom, for example – thus skewing the calcium content towards the higher side of the spectrum.

Therefore, exercise caution when eating something containing flour if you haven’t prepared it yourself, or if you are unable to know for sure what’s its true calcium content.

Calcium in bread

Bread made from white wheat is listed as having 684 milligrams of calcium per 100 grams – about 4 slices.

That’s a lot, especially when you consider that the recommended daily allowance for calcium is 1000 milligrams for men under 70 and for women under 50 – if you are older, pregnant, or breastfeeding, your recommended daily requirements go up to 1200 milligrams per day.

Cornbread, prepared from recipe, made with low fat (2%) milk, has 249 milligrams per 100 grams.

A commercial preparation of whole-wheat bread contains 161 milligrams.

However, wheat bread is listed again by the USDA as having just 125 milligrams, evidencing that the other white bread referred to a recipe containing a fortified flour.

These wild variations are worth noting when you are striving to avoid calcium-enriched foods.

Therefore, once more, the question is:

Do you know what’s in your bread?

If you do and can be sure it doesn’t contain any added calcium carbonate, you can eat a few slices guilt free.

Rule 13: Be sure to eat a portion of leafy greens vegetables every day

Leafy greens are great, but they’re also good sources of calcium.

Should you really be eating them?

It’s worth noting that the Coimbra Protocol diet is a low-calcium diet, not a no-calcium diet.

Just like with vitamin C, Your goal is to limit your calcium intake, not restrict it entirely.

After all, no one can survive without calcium or without vitamin C.

It’s just that, thanks to a helping hand from vitamin D, your intestines will be working much harder at extracting every bit of calcium they can from the foods you eat.

This means that if a regular person and someone on high doses of vitamin D both drink a glass of milk each, the person taking the vitamin D will absorb a much greater quantity of the calcium available in that milk.

While you are on the protocol, you’ll still have the same need for 1000 milligrams of calcium – or 1200 if you are old, pregnant or breastfeeding.

You’ll just have a much easier time reaching that level – and much greater problems if you exceed it.

Similarly, even though any vitamin C will tend to break down into oxalates, it's the daily excess of ascorbic acid that can prove problematic. And, such an excess will be hard to achieve unless you are consciously supplementing with high doses of this vitamin.

Therefore, you need to decide if you’ll be getting your calcium from dairy or from leafy greens.

Dr. Coimbra’s opinion seems clear: cut out the dairy and get your calcium from your daily portion of leafy greens instead. Ditch the vitamin C supplements and get your ascorbic acid from natural sources.

Will your Coimbra protocol Doctor prescribe you this exact same diet?

It depends.

As you can see from rule number 7, avoid eating too much açai, the Coimbra protocol diet was designed to fit into the Brazilian culture and lifestyle.

Depending on where you live, there might be other calcium-rich foods lurking around, not indexed by the USDA – and thus not in my list of foods to be careful about.

Some of those unique eating, or drinking, habits may even interfere with vitamin D absorption and metabolism or even easily overload your kidneys with oxalates.

On top of that, your health history may require you to make certain changes to the diet.

For example, if you are diabetic, suffer from osteoporosis, or have a history of hypocalcemia – low blood calcium – your Doctor may decide to make key changes to the rules of the diet.

That’s why it’s key that you understand not only the rules but the logic behind the whole protocol.

The why behind each recommendation.

Once you understand this logic, you’ll never look at high-dose vitamin D therapy in the same way.

Suddenly the complex becomes simple and you understand exactly what to do next and why you need to do it.

I’ve prepared a book that guides you through this journey.

It includes information on diet, lifestyle changes, supplement dosages and easy-to-follow instructions on how to interpret your blood and urine test results and adjust your vitamin D and vitamin K2 dosage accordingly.

Be sure to check out the free chapters available on its amazon page.