5 Heart Healthy Reasons to Eat Spinach and other Leafy Greens Daily

Popeye was right….see below…

1. Enrichment in Vitamin K. Vitamin K is an essential vitamin that helps to regulate bone health and blood clotting.  The minimum recommended daily intake is 90 micrograms (mcg) for women and 120 mcg for men. Vitamin K deficiency is most commonly the result of reduced dietary intake, digestive problems (such as malabsorption) and liver disorders.  In addition to increased risk of bone fractures and bleeding recent studies also suggest that low levels of Vitamin K may be linked to cognitive decline and higher risk of Alzheimer’s disease. Fortunately, leafy greens come to the rescue because of their high content of Vitamin K in relatively small quantities. For example, eating just 5-10 kale chips will provide a day’s worth of your Vitamin K needs.  Other leafy greens that are rich sources of Vitamin K include spinach, collards and beet greens.  A word of caution is urged for those prescribed blood thinners such as coumadin (warfarin) that interfere with Vitamin K.  Make sure to speak to your health care provider- we recommend that you consume the same amount of leafy greens each day to avoid significant fluctuations in “INR”.
2. Enrichment in Natural Nitrates. Dietary nitrates (not to be confused with cancer promoting artificial nitrates used in processed foods), are mostly (~80%) derived from vegetables.  When chemically converted to nitric oxide the result is blood vessel dilation, reduced blood pressure and improved vascular health.  Foods highest in nitrates include the leafy greens, arugula, chard, kale and spinach.  In addition to vascular health, an Australian study found that eating at least 1 cup of green leafy vegetables per day enriched in cabbage, kale, lettuce and spinach was associated with stronger muscle function that was independent of physical activity.  The mechanism is believed to be due to nitric oxide mediated  improvement in muscle contractility as previously demonstrated with heart failure.
3. Enrichment in Folate. One serving of spinach contains 2/3rds of the daily requirement of folate (Vitamin B9). Folate is key for both heart and emotional health.  By helping to regulate levels of the amino acid homocysteine, a risk factor for heart attack and stroke, high intake of folate may be associated with reduced risk.  In addition to spinach, other dark leafy greens high in folate are Turnip greens; one serving will provide ~40% of your daily requirement.  Because low folate levels are also associated with depression, a daily serving of spinach can also be mood uplifting (see also Magnesium below)!

4. Enrichment in Potassium. Leafy greens from arugula to turnip greens are important sources of potassium, a pivotal mineral for regulating blood pressure. The DASH diet (Dietary Approaches to Stop Hypertension) is among the most effective for reducing blood pressure. Leafy greens are an important component of a potassium-rich diet, designed to help dispose of excess sodium.  The daily potassium goal from foods ranges between 3,500–4,700 mg and just a single cup of the following leafy greens will provide a good chunk of change as you aim for your daily goal; they are Beet greens (1300 mg), Swiss chard (960 mg), spinach (840 mg) and Bok choy (630 mg).

5. Enriched in Magnesium: It has been estimated that nearly 3 of 4 Americans do not fulfill their dietary intake of magnesium (men: 400-420 mg; women: 310-320 mg).  If you are deficient in magnesium, you may experience muscle cramps, fatigue and/or an abnormal heart rhythm.  Low magnesium levels are also linked to depression, anxiety and panic attacks.  Fortunately, cooked spinach is an excellent source of magnesium with 1-cup providing 50% of the recommended daily amount for Olive Oyl (and other women).  With that said, can you think of a better ambassador for this post than the sailor man himself?                                                                                                                                                      Michael Miller, MD is Professor of Cardiovascular Medicine at the University of Maryland School of Medicine in Baltimore, Maryland  and author of “Heal Your Heart: The Positive Emotions Prescription to Prevent & Reverse Heart Disease” published by Penguin Random House.

Redefining the Physically Fit Heart

When evaluating fitness levels, a basic question is whether my (ambulatory) patients can walk up 2 flights of stairs (~20-30 steps) without stopping.  The answer is most revealing when they disclose the need to stop to catch their breath and/or experience heart-related symptoms that are new or progressive.

A new study helps to redefine the physically fit heart.  Conducted in Spain, study volunteers climbed 4 flights of stairs (60 steps) at a fast but comfortable pace.  Those able to complete this task within 45 seconds were found to have a heart workload ~10 METS; this workload was associated with a normal stress test (and presumably, normal heart function), in the vast majority of study subjects.  By contrast, stair climbing that took at least 90 seconds (correlating with a heart workload of less than 8 METS) was associated with an abnormal stress test (and presumably, heart disease) in ~60% of study volunteers.

The Metabolic Equivalent of Tasks (METS) is the amount of energy used during physical activity.  One MET equals activity at rest with higher levels representing increased intensity of a given activity.  From a cardiovascular standpoint, a physically fit heart is one that is able to generate a workload of at least 10 METS, as demonstrated by the stair climbing activity above ; this translates to a low annual cardiovascular death rate (1% and lower).  Inability to achieve 8 METS, however, translates into a considerably higher annual cardiovascular death rate (2% and greater), a rate typically observed in men and women with established heart disease.

(For the record, I clocked in at 37 seconds (with surgical mask-on) for my 60-step jaunt earlier this week en route to my outpatient cardiology center).

Listed below are several tips I make to my patients regarding exercise for the heart.  More detailed recommendations can be found in my chapter Lighthearted and Light on Your Feet from “Heal Your Heart”.

1. Aim to walk approximately 5 miles a day:  Keep track of your daily activities using a pedometer or similar tracking device (iphones have a built-in “health app” that automatically tracks your daily activities).  Every 2,000 steps equal ~1 mile; 10,000 steps is equivalent to 5 miles.
2. Aim for a walking rate of 3-5 miles per hour (mph):  When it comes to heart health, the sweet spot is walking at a “brisk” rate of 3 to 5 mph.  If you are walking on a treadmill, start off with a 5-10 minute warmup period (2-3 mph), then engage in the higher walking rate for 20-30 minutes followed by a 5-10 minute cool down period.
3. Arise and stretch every 20-30 minutes at work: In the age of COVID, many of us have spent more time working from home. If you have a sedentary job, make sure to stand and stretch at least twice each hour.  When watching TV, I advise my patients to stand up and stretch during commercials.   Stand and stretch twice each hour when watching Netflix, Amazon or other movies at home.
4. Build in light weight toning and stretching exercises:  A healthy physical activity regimen should incorporate light weights and stretching to stabilize and improve balance & coordination in order to reduce fall risk.  Engaging in aerobic activities and weight toning exercises, reduces cardiovascular risk by 20-30%.
5. Try Walking Backwards at Home: Walking backwards has been shown to improve balance, coordination and various brain functions such as attention span and memory. Find the longest room in their home and start walking forward and backward for 5 minutes on day 1 with progression to 10-15 minutes daily.

Michael Miller, MD is Professor of Cardiovascular Medicine at the University of Maryland School of Medicine.  Check out his HeartHealth Tip of the Day on Twitter @mmillermd1 and book “Heal Your Heart…” at your library, bookstore or online.

TEAing up for Heart Health

One of my fondest childhood memories was visiting my great-grandmother.  Her savory Hungarian cuisine was inevitably topped off with a slice of homemade Gerbeaud cake served with a glass of ginger lemon tea.  Over the years,  traditional black/green and herbal teas have become a staple in our home.  As one of the heart healthiest beverages, 2-3 cups/glasses of tea each day reduces the risk of a heart attack/stroke by 20%!

Tea contains powerful antioxidants (such as polyphenols and catechins) and protects the heart by:

1. Reducing toxic free radicals that promote cellular aging.
2. Revving up fat metabolism to lower abdominal (or belly) fat.
3. Dilating blood vessels for blood pressure lowering.
4. Inhibiting blood clot formation.
5. Improving mood and serenity.

Other heart-healthy properties of tea include 30-40% reduction in triglycerides, 15-20% lowering of blood glucose, and blunting of age-related decreases in HDL (the good cholesterol).

Among the most highly desirable teas is Argentinian Maté. In this category, I highly recommend Yerba Maté from Soul Maté.  For my patients, I recommend 5 of the following teas based on flavor and heart-protective properties.

1. Borage:  In animal models, borage tea reduces cholesterol and liver fat . Excessive liver fat is associated with the development of the metabolic syndrome and Type 2 diabetes, both of which raise cardiovascular risk.
2. Butterfly Pea Flower: Known as “blue tea” because of its color, a single cup can reduce anxiety and uplift mood to improve emotional/heart health.  As picture above, my daughter Ilana is savoring an after dinner glass.
3. Hibiscus: Drinking 2 cups of hibiscus tea daily reduces systolic blood pressure ~5-10 mmHg.
4. Yerba Maté: One of South America’s liquid gems, this tea is an antioxidant powerhouse with heart protective properties that reduce cholesterol, improve glucose control and keep inflammation at bay.
5. Valerian:  For a more restful night’s sleep, try a cup of Valerian root tea.  The Valerian root contains a high concentration of the mood stabilizing chemical GABA that enables relaxation and better sleep quality.

Michael Miller, MD is Professor of Cardiovascular Medicine at the University of Maryland School of Medicine.  Check out his book “Heal Your Heart…” for the Top 50 Heart Healthiest Foods/ Beverages..

Do You Know Your Lp(a) Level?

While many of us know our cholesterol (including both good [HDL] and the bad [LDL] levels), I bet that very few can say the same about Lipoprotein(a), also known as “Lp(a)”, even though we’ve long known how dangerous high levels can be.  In fact, my longstanding friend and colleague, Dr. Tom Pearson referred to Lp(a) as the “Heart Attack Maker” more than 30 years ago!

So why has Lp(a) been left out of the spotlight, especially when compared to LDL and other well-established promoters of cardiovascular disease?  The simple answer is that until recently, we did not have powerful or effective Lp(a) lowering therapies.  Secondly, and equally important is that we still don’t know whether lowering Lp(a) will translate into a reduced risk of a future heart attack or stroke.  With more effective therapies available or in clinical trial testing, we should now, more than ever, know our Lp(a) level.   Here’s why:

1. Lp(a) increases risk of cardiovascular disease: One might consider Lp(a) as “the bad cholesterol” on steroids. That’s because Lp(a) consists of LDL plus the protein, apo(a), that is chemically similar to the clot buster, plasminogen. By binding to specific chemical (lysine) sites normally activated by plasminogen, apo(a) inhibits this process. As a result, blood clotting increases rather than decreases.  In other words, Lp(a) not only promotes cholesterol plaque buildup in the coronary arteries (as mediated by LDL) but also sets up a blood clotting environment that is ripe for the so-called “coronary thrombosis”, a medical term for a heart attack composed of clotted blood that overlies a cholesterol plaque and obstructs blood flow in a coronary artery.  A normal level of Lp(a) is less than 75 nmol/L (or 30 mg/dL).  The 2018 Cholesterol Guidelines published by the American Heart Association/American College of Cardiology defines high risk levels as 125 nmol/L (50 mg/dL) and greater.  The risk of heart attack, stroke and valve disease (aortic stenosis) increases 2-4 fold in those with very high compared to normal Lp(a) levels.
2. Lp(a) increases the risk of premature heart disease: A group at particularly high risk of premature heart disease due to high Lp(a) are South Asians (ancestral origins from India, Pakistan, Bangladesh and Sri Lanka) where ~1 in 4 has levels exceeding 125 nmol/L and where the risk of heart attack or stroke is collectively higher than in European White populations.  Similarly, Black Americans have ~2-4 fold higher Lp(a) levels than White Americans with elevated levels associated with an increased risk of cardiovascular disease.   In some instances, high Lp(a) levels are only discovered after premature heart disease has set in.  A case in point is a young patient I evaluated a number of years ago.  She was in her 20s when she suffered a heart attack and had coronary bypass surgery.  In my experience, women who have experienced a heart attack under the age of 40 have been heavy cigarette smokers (at least a pack a day), smoked cigarettes and used birth control pills, were drug users (cocaine), had extremely high LDL (see below) or had diabetes for at least 10 years.  My patient had none of these risk factors.  However, when we checked her Lp(a) levels, they were in the 500 nmole/L range- more than 4 times the normal range! (you can read about her case here)
3. The combination of high Lp(a) and high LDL is very worrisome:While having a high Lp(a) or a high LDL cholesterol will each raise the risk of heart disease, the combination of high/high markedly accelerates risk.   I evaluated a woman in her early 30s who came to see me after her brother, a college track star died suddenly.  His autopsy revealed a near total occlusion of his left main coronary artery.  While they both had elevated LDL (in the 200-300 mg/dL range), Lp(a) levels had never been assessed.  As it turns out, her Lp(a) was also very high (~250 nmol/L).  There are only a few conditions where severe coronary disease occurs in such a young person.  With respect to cholesterol, genetic conditions include 1) homozygous familial hypercholesterolemia (FH) (LDL ~600-800 mg/dL) or extremely high Lp(a) [as our case illustrated above] and 2) heterozygous FH (LDL ~300-400 mg/dL) plus a 2^nd risk factor (high Lp(a), smoking and diabetes).  Needless to say, anyone with a family history of premature heart disease should have their Lp(a) levels assessed. The good news is that Lp(a) levels are relatively stable and in the absence of treatment (see below) do not change significantly over time.
4. Lp(a) can be lowered by new treatments: What can you do to lower high Lp(a) levels? Although lifestyle therapy is the cornerstone in the prevention and management of heart disease, Lp(a) levels are stubbornly resilient to these measures.  Even cholesterol lowering medications such as statins are ineffective for lowering an elevated Lp(a).  However, the newer and powerful class of non-statin cholesterol lowering medications referred to as “PCSK9 inhibitors” can lower Lp(a) levels upwards of 30%.  A highly effective method for lowering Lp(a) is through plasma exchange or “lipoprotein apheresis”.  However, while a single session lowers Lp(a) levels ~50-75%, the process needs to be repeated ~every 2 weeks with a sizeable time commitment depending upon the location of the medical center conducting this procedure. The big question that remains is does lowering high levels of Lp(a) reduce cardiovascular events, such as heart attacks and strokes.  Fortunately, a new (once monthly injectable) therapy will be studying this question. Known as “Lp(a) antisense therapy”, genetic material [single-stranded DNA antisense oligonucleotide binds to apo(a) mRNA) blocks production of the Lp(a) protein; the result is a dramatic reduction in Lp(a) levels upwards of 80%!  An international clinical trial is currently underway to test whether lowering Lp(a) will indeed reduce risk of future cardiovascular events.  You may qualify for the HORIZON study, if your Lp(a) level is at least 175 nmol/L (70 mg/dL) and have experienced a heart attack or stroke within the past 10 years. The University of Maryland School of Medicine is a site for this trial; if you are interested and live in/around the Baltimore region, contact us at 410 328-8790 to set up a screening visit.

Michael Miller, MD is Professor of Cardiovascular Medicine at the University of Maryland School of Medicine.  Check out his HeartHealth Tip of the Day on Twitter @mmillermd1 and book “Heal Your Heart…” available online, at your library or bookstore.