Rosane Oliveira, DVM, PhD - Forks Over Knives https://cms.forksoverknives.com/contributors/rosane-oliveira-dvm-phd/ Plant Based Living Wed, 07 Dec 2022 09:15:19 +0000 en-US hourly 1 https://wordpress.org/?v=6.2.2 https://www.forksoverknives.com/uploads/2023/10/cropped-cropped-Forks_Favicon-1.jpg?auto=webp&width=32&height=32 Rosane Oliveira, DVM, PhD - Forks Over Knives https://cms.forksoverknives.com/contributors/rosane-oliveira-dvm-phd/ 32 32 Why Olive Oil Is Not Healthy for Your Heart https://www.forksoverknives.com/wellness/why-olive-oil-is-not-healthy-for-your-heart/ https://www.forksoverknives.com/wellness/why-olive-oil-is-not-healthy-for-your-heart/#respond Wed, 14 Feb 2018 18:57:03 +0000 https://www.forksoverknives.com/?p=57990 Olives conjure up images of the warm sun and deep blue seas of the Mediterranean, where the olive tree flourishes. In more...

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Olives conjure up images of the warm sun and deep blue seas of the Mediterranean, where the olive tree flourishes. In more recent times, olive oil has enjoyed similar admiration.

Considered by many as a staple in any serious kitchen, olive oil has also achieved mythic stature as the ultimate healthy ingredient, protecting us from heart disease. But does olive oil really deserve its heart-healthy reputation?

Like any other oil, olive oil is a processed, concentrated fat extract and thus has lost most of the nutritional value of its original form (the olive itself). If you want nutritional value, you will find it by eating the whole olive—not by consuming it in its almost unrecognizable extracted oil form. (But even olives should be eaten in moderation due to their high fat and sodium content.)

The bottom line is that the fats we need should come in nature’s original package—whole plant foods!

A Quick Lesson in Cardiovascular Health

To evaluate whether or not olive oil is indeed heart-healthy, we first need to understand a few facts about vascular biology.

The vessels in our entire cardiovascular system are lined with highly functional endothelial cells. These cells provide a barrier between the blood and the rest of the body tissues and are involved in blood clotting, the formation of new blood vessels, and recruitment of immune defense cells. Endothelial cells also produce nitric oxide, which makes blood vessels dilate to increase blood flow and prevent platelets from sticking to the vessel walls.

Impaired endothelial function is a hallmark of vascular disease, considered an early event in the development of atherosclerosis, and seen in patients with high blood pressure, high cholesterol, coronary artery disease and type 2 diabetes.

A noninvasive method to test endothelial function is Flow Mediated Dilation (FMD), which uses ultrasound to measure flow-mediated changes in the diameter of the brachial artery. Healthy endothelial cells will respond to a stimulus by releasing nitric oxide and causing the brachial artery to dilate, while unhealthy cells will not. In other words, the level of dilation, measured via ultrasound, is a good indication of the overall health of the vessels in the cardiovascular system.

Olive Oil and the Heart

Not surprising, significant FMD impairment can be seen after someone smokes or eats a lot of fat, sugar, and/or salt in a meal. FMD impairment is also detected when someone suffers from mental stress or a chronic disease like high cholesterol or diabetes.

So what is the effect of olive oil on FMD? All oils, both animal and plant derived, tend to worsen endothelial function. Within hours of ingesting fat, arteries stiffen and the ability to dilate is impaired. A 1999 study measuring FMD after the ingestion of high-fat meals reported a “three-hour decline in FMD after subjects ingested a traditional meal of a hamburger and fries or cheesecake. Olive oil was found to have the same impairment to endothelial function as the rest of these high-fat meals.” And a 2007 study showed a similar detrimental effect on endothelial function after the intake of olive, soybean, and palm oils.

Is Extra Virgin Olive Oil a Healthier Choice?

In a cohort study designed to measure the effects of a Mediterranean diet as the primary prevention of cardiovascular disease, extra virgin olive oil (EVOO) was shown to be better than regular olive oil, but neither significantly reduced heart attack rates. Other studies report similar findings, showing that EVOO damages endothelial function just like its ‘regular’ olive oil counterpart.

In the PREDIMED study, 7,447 people at high risk for cardiovascular disease were randomly placed into three groups. One group was told to eat a Mediterranean diet using only EVOO (up to 1 liter per week!). The second group ate a Mediterranean diet and added a half-pound of nuts per week. The third group, the control group, was told to reduce fat intake (but it didn’t).

After five years, the conclusions were stunning; there were nearly no differences between groups. No differences in weight, waist circumference, systolic and diastolic blood pressure, fasting glucose, or lipid profile.

And no difference in the number of heart attacks or deaths from cardiovascular disease; those in the EVOO group suffered just as many heart attacks and cardiovascular disease as those in the control group. (There was a significant reduction in the number of strokes, but that reduction was greater in the group that ate nuts.)

The Mediterranean Diet Is Healthful in Spite of Olive Oil

It appears that the low heart disease rate associated with a Mediterranean diet is in spite of olive oil—not because of it! In other words, the ‘heart-healthy’ Mediterranean diet is due to the high consumption of whole plant foods rather than the olive oil, which usually accompanies all those vegetables. In fact, studies to measure the effects of the Mediterranean diet on endothelial function showed FMD impairment after meals rich in olive oil.

Scientists concluded that the Mediterranean diet’s heavy “inclusion of antioxidant-rich fruits, vegetables, and their products apparently provide some protection against the direct impairment in endothelial function produced by high-fat foods, including olive oil.”

These results were confirmed in another study showing that adding vegetables to a fatty meal may (at least partially) restore arterial function and blood flow.

Olive Oil Gives Power to the Plaques

In addition, it appears that olive oil can contribute to atherosclerosis. Atherosclerosis is the narrowing of blood vessels due to the buildup of waxy ‘plaques’—clumps of fat and debris—along the vessel walls. The vessels become narrow and rigid, making the heart work harder to deliver oxygen to our bodies and increasing the risk of heart attacks.  To make matters worse, the fat in the plaques is easily oxidized, releasing dangerous free radicals that further damage blood vessels.

When comparing baseline with one-year follow-up angiograms in people with coronary heart disease, saturated animal fat, monounsaturated (olive oil) and polyunsaturated fats were all associated with significant increase in new atherosclerotic lesions. The lesions stopped growing only by decreasing all fat intake—from whatever source.

Less Damage is Still Damage

Many argue that olive oil is a better alternative than other saturated fats. While there is some truth to this (olive oil does appear to cause relatively less damage than saturated animal fats), it is important to note that ‘less damage’ is still damage.

The scientific evidence clearly shows that olive oil plays a role both in damaging blood vessels as well as forming atherosclerotic plaques. ‘Causing less damage’ is a far cry from ‘promoting heart health’ as so many people believe is the case with olive oil.

The bitter truth is that, as Dr. Caldwell Esselstyn points out, “Between 14 and 17 percent of olive oil is saturated, artery-clogging fat—every bit as aggressive in promoting heart disease as the saturated fat in roast beef.”

If you are just starting on your plant-based journey, keeping tiny amounts of extra virgin olive oil may help you enjoy your starches and veggies more and guarantee that you ‘stick’ to the diet. It is indeed better than using other oils or fats, and much better than continuing to eat a standard American diet.

However, if you want to continue to improve on your plant-based diet and make it predominantly whole foods, the recommendation is to stay away from olive oil altogether—even the extra virgin variety.  So just opt out of olive oil.

The true heroes of a heart-healthy diet are whole grains, legumes, vegetables, fruits, and nuts, so embrace these foods and enjoy their benefits.

Your heart will thank you for it.

Ready to get started? Check out Forks Meal Planner, FOK’s easy weekly meal-planning tool to keep you on a healthy plant-based path. To learn more about a whole-food, plant-based diet, visit our Plant-Based Primer.

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Getting Clarity About Calcium https://www.forksoverknives.com/wellness/milk-myth-why-you-dont-need-dairy-for-calcium/ https://www.forksoverknives.com/wellness/milk-myth-why-you-dont-need-dairy-for-calcium/#respond Fri, 22 May 2015 00:01:11 +0000 http://www.forksoverknives.com/?p=24990 The subject of calcium is a hotly debated one. One of the biggest controversies is whether or not we can really get...

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The subject of calcium is a hotly debated one. One of the biggest controversies is whether or not we can really get enough calcium following a whole-food, plant-based diet that excludes dairy.

Here are some of the more common questions:

  • How much calcium do I really need?
  • Can I really get enough calcium eating just plants?
  • What is calcium absorption, and why is it important?
  • What factors (or foods) make me lose calcium?
  • Can’t I just fix everything by taking calcium supplements?

To help clarify this important topic, let’s tackle each of these calcium questions one at a time:

How Much Calcium Do I Really Need?

The current daily recommended allowance for calcium for most adults is 1,000 to 1,200 milligrams. However, plant-based health experts believe these requirements are high for a simple reason: a diet high in animal protein has a high excretion rate, which means you are forced to consume more calcium to make up for the inherent calcium excretion. When following a whole-food, plant-based diet (that is also low in sodium and caffeine), calcium excretion rates are much lower, which logically means that a plant-based eater’s calcium intake can also be much lower.

How much lower? A study published by the American Journal of Clinical Nutrition showed that “individuals with low, but nutritionally adequate, intakes of sodium and protein may have calcium requirements as low as 500–741mg/day.”

Can I Really Get Enough Calcium Eating Just Plants?

Like iron, magnesium, and copper, calcium is a mineral. It is found in the soil, where it is absorbed into the roots of plants. Animals get their calcium by consuming these calcium-rich plants. So even though we are all conditioned to believe that calcium comes from milk and dairy products, the real source of calcium richness is the earth. No wonder that a whole-food, plant-based diet has plenty of calcium.

A varied diet of starches, vegetables, and fruits (without dairy) has sufficient calcium to meet our needs. If you eat a relatively low-calcium diet, your body will adjust. Studies show that when fed a relatively low-calcium diet (415 mg/day), our intestines become more efficient at absorbing calcium, and our kidneys conserve it better. Equally, when overfed with calcium (1,740 mg/day) our bodies adjust as well: our intestines block the calcium absorption, while our kidneys eliminate more. This is an example of how our bodies protect us: if not eliminated, the excess calcium would get deposited in our soft tissues (heart, kidneys, muscles, and skin), making us vulnerable to illness and even death … a true testament to how smart our bodies really are!

So your needs are met. Always.

At the end of the day, the “disease” of calcium deficiency from a calorically sufficient natural whole-food plant-based diet is nonexistent.

How Much of the Calcium I Eat Is Actually Absorbed?

The amount of calcium we ingest may be less important than how much we actually absorb. For example, 1 cup of milk contains about 300 mg of calcium. But only about 30% of it (90 mg) is actually absorbable, and thus bioavailable (available to our bodies).

Let’s compare the calcium content and absorption rate of cow’s milk versus some plant-based alternatives:

  • The calcium in firm tofu has about the same absorption rate as dairy products, hovering around 31%. And while ½ cup of tofu yields the same amount of calcium as 1 cup of milk (300 mg), it contains more protein, far less saturated fat, and about a tenth of the sodium.
  • Calcium-intense vegetables like Chinese mustard greens enjoy absorption rates of around 40%. In terms of calcium content, 1/2 cup of these cooked greens will give you as much calcium as one glass of milk.
  • One cup of bok choy, 1½ cups of kale, or 2 cups of broccoli contain the same amount of calcium as a glass of milk, due to their much better calcium absorption rate (in the 50–60% range! )

What Factors (or Foods) Make Me Lose Calcium?

Many factors contribute to calcium loss, from age (older people lose more calcium) to vitamin D status (people who test low for vitamin D3 tend to lose more calcium) to the concurrent contents of your intestines. Sodium, protein, and caffeine play primary roles in calcium loss.

  • Sodium: Sodium is our biggest enemy when it comes to calcium loss. For each 1000 mg of sodium (2,500 mg of table salt) excreted by the kidneys, about 40–60 mg of calcium goes with it.
  • Protein: As the intake of dietary protein increases, so does the urinary elimination of calcium. So when you double your protein, your calcium loss through urination increases by 50%.

The propensity of protein to cause calcium loss is particularly interesting when it comes to dairy products, which have always been considered as one of the best calcium sources. You lose 1/3 of the calcium you get from milk and over 2/3 of the calcium you get from cheeses.

  • Caffeine: Caffeine also seriously affects the body’s ability to retain calcium, as it acts as a diuretic and pulls calcium out from the body.

In stark contrast, many leafy green vegetables provide lots of easily absorbed calcium without causing calcium loss!

Can’t I Just Fix Everything by Taking Calcium Supplements?

Even though studies show that supplementing with calcium can reduce the risk of fractures by 10% (hip fractures excluded), doing so can also increase our chances of cardiovascular disease and strokes, cause kidney stones, and induce gastrointestinal distress.

According to the results of a recent randomized, double-blind, placebo-controlled study of over 36,000 post-menopausal women, “Calcium supplements with or without vitamin D are associated with an increased risk for MI (myocardial infarction) and stroke, and this risk appears to apply across subgroups defined by important baseline characteristics. These findings suggest that targeted prescription of calcium supplements to specific population subgroups, such as younger people and those with low dietary calcium intake, should not be endorsed.”

But If We Don’t Drink Milk or Take Calcium Supplements—What Happens to Our Bones?

A recent study addressed this very important question, comparing the bone mineral density of long-term vegans versus omnivores. The results were astounding; even though the vegans have vastly lower dietary calcium and protein intakes, they enjoyed the exact same bone density as their meat-eating counterparts.

In conclusion, you don’t need dairy or supplements to get enough calcium (in fact they may be a hindrance rather than a help). As long as you eat a calorically sufficient whole-food, plant-based diet that drastically reduces or completely eliminates added sodium, you’ll get all the calcium you need.

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