When it comes to the leafy greens you put in your salads, not all are created equal.
So which leaves and lettuces should you use in your salad to justify the croutons, bacon, and tasty dressing you add?
We’re here to help you find the most nutritious ones.
In similar rankings published in the past, we’ve relied on the CDC’s 2014 list of “powerhouse foods”. But this time, we factored in how many nutrients (specifically potassium, fiber, protein, riboflavin, niacin, folate, B6, calcium, iron, zinc, and vitamins A, C, and B6) the greens pack per calorie.
Of course, none of the veggies on this list are bad for you, and you won’t necessarily be worse off for picking one over another.
This article was initially posted in June 2017.
12. Arugula (sometimes called rocket)
Arugula’s distinct peppery taste doesn’t quite correlate with a high nutritional content. While it does have some vitamins, it lacks other nutrients that other greens boast.
Calories per cup: 6
11. Iceberg lettuce
- William Wei, Business Insider
It’s no surprise that iceberg lettuce is among the least nutritious greens to put in a salad. In fact, Chick-fil-A has even banned the veggie from its stores, allegedly because of its low nutritional value. Iceberg lettuce has about only 7% of your daily vitamin A per cup, and only 3% of daily vitamin C – among the lowest on this list.
Calories per cup: 10
- Wikimedia Commons
Radicchio is a member of the chicory family. It’s packed with vitamin K, containing more than 100% of your daily value.
Calories per cup: 9
TIE – 8. Watercress
Watercress, with its little round leaves, was considered the top powerhouse food in the CDC study. However, by our metrics, it didn’t pack in as many nutrients as others on the list. It’s high in vitamins A, C, and K and incredibly low in calories.
It’s also linked to a lower risk of type-2 diabetes and is not too hard to grow.
Calories per cup: 4
TIE – 8. Leaf lettuce
- Wikimedia Commons
One of the more nutritious of the lettuce family, leaf lettuce is low in calories and high in potassium and vitamins A and K.
Calories per cup: 5
Endive, also a kind of chicory, is fill of vitamin K, and a cup has 20% of your daily vitamin A intake. The frisée – or curly endive – in salads is also part of this plant.
Calories per cup: 8
With its defining red (or rainbow) stems, chard is among the top powerhouse foods because of its low calorie count and high levels of nutrients. It has the most vitamin K of any leafy green on this list, at nearly 300% of your daily value per cup. Chard also contains a fair amount of magnesium, which is important for things like muscle and nerve function, blood-glucose control, and blood-pressure regulation.
Calories per cup:7
5. Butter lettuce
- Flickr/Anita Hart
Also called Boston or bibb lettuce, butter lettuce is the most nutritious of the lettuces on this list. The leaves are higher in folate, iron, and potassium than iceberg or leaf lettuces.
Calories per cup: 7
- liz west/Flickr
Romaine ranked among the top 10 “powerhouse foods,” by the CDC, which are classified based on their associations with reduced risk for chronic diseases. It’s an especially great source of vitamin A – one cup has 81% of your daily intake – as well as some B vitamins.
Calories per cup: 8
3. Broccoli leaves
While most folks just eat the heads of broccoli (and maybe the stems) tossing some of the plant’s nutrient-packed leaves into your salad can be a good decision. The leaves are high in protein and have the highest fiber and vitamin A content of the greens on the list.
Popular chain Sweetgreen even started featuring them in seasonal salads after conversations with farmers.
Calories per cup: 13
TIE – 1. Spinach
Spinach is a staple green in many salads that feature sweet ingredients like beets or fruit. It’s also one of the top-ranking greens when it comes to all-around nutrition content. It’s packed with vitamins and nutrients, particularly potassium and iron, which are important for regulating your blood cells and blood pressure. Unfortunately, spinach is not as high in protein as Popeye may have led you to believe.
Calories per cup: 7
TIE – 1. Kale
- Laurel F/flickr
Trendy for a reason, kale kills it in vitamin content, especially A, C, and K. Vitamin K is especially important in helping blood to clot.
Calories per cup: 33
- Chung Sung-Jun/Getty Images
- The CDC recommends getting seven to nine hours of sleep per night, but individual needs vary.
- Sleep deprivation is associated with serious health issues, including increased risk for obesity, diabetes, high blood pressure, and stroke.
- Here are five factors that will help you figure out what your sleep patterns are and how they compare to the larger population.
In theory, sleep should take up about eight out of every 24 hours, a third of our lives.
But many of us don’t actually sleep that much and are tired all the time. More than one third of Americans don’t get the seven to nine hours of sleep per night that the CDC recommends, and according to research by the National Sleep Foundation, more than a third of Americans say their sleep quality is “poor” or “only fair.”
That’s certainly true for Tesla CEO Elon Musk, who recently told the New York Times that he’s been logging 120-hour work weeks. Musk acknowledged that his exhaustion is likely taking a toll on his health.
“It’s not been great, actually,” Musk told the Times. “I’ve had friends come by who are really concerned.”
So how much sleep do we really need?
Like most health factors, there isn’t a one-size- fits-all answer – sleep needs vary from person to person. There are some incredibly rare people who can actually get by on a few hours of sleep per night, and others on the opposite end of the spectrum that doctors refer to as a “long sleepers” because they need 11 hours nightly.
But research on sleep can help you figure out how much you need and how to better get a night’s rest. Here are five facts that will help you figure out what your personal sleep patterns are and how they compare to the rest of the population.
There’s a reason that doctors recommend seven to nine hours of sleep
- Notice, the vast majority of people need between seven and nine hours of sleep.
- Internal Time: Chronotypes, Social Jet Lag, and Why You’re So Tired by Till Roenneberg
The amount of sleep people need falls into a bell-curve distribution: the vast majority of the population needs between seven and nine hours of rest each night to be refreshed.
The chart to the right, from the book “Internal Time: Chronotypes, Social Jet Lag, and Why You’re So Tired” by German chronobiologist Till Roenneberg, shows the general distribution of sleep needs. (Chronobiology is the science of our internal clocks.)
According to CDC data, getting less than seven hours per night is “associated with increased risk for obesity, diabetes, high blood pressure, coronary heart disease, stroke, frequent mental distress, and all-cause mortality.”
Sleep deprivation can also hurt cognitive performance(as many of us have probably experienced), and that in turn “can increase the likelihood of motor vehicle and other transportation accidents, industrial accidents, medical errors, and loss of work productivity,” the CDC says.
You have a natural chronotype, or body clock, that determines when you are most comfortable sleeping and being awake
Most of us think of ourselves as morning or night people, but those divisions aren’t scientific – they’re just ways of comparing ourselves to one another.
“Where you define owl or lark is really arbitrary,” says Dr. David Welsh, an associate professor studying circadian clocks at UC San Diego.
Welsh says that if you look at large surveys of populations, you get a normal distribution of chronotypes – most people have fairly “average” chronotypes, some prefer to get up a bit earlier or later, and small groups naturally rise extremely early or late. There’s no line that distinguishes different chronotypes.
But we all have an internal schedule that makes us feel awake or sleepier at different times of day. Because of factors including hormone levels, genetics, and light exposure, some of us are more alert in the mornings and some of us prefer times later in the day.
If your schedule isn’t aligned with your chronotype, you will feel tired and out of sync.
The amount of sleep you need changes throughout your life
- National Sleep Foundation
The seven-to-nine-hour rule is standard for adults, but kids need much more sleep, while some older people need less.
This chart by the National Sleep Foundation shows how these requirements change as kids grow up.
In addition to sleep hour needs changing, chronotypes change throughout life as well.
According to Roenneberg’s book, young children naturally tend to be more morning oriented. Around puberty, they’re more likely to shift into a night owl chronotype, which tends to shift back to an earlier chronotype after age 20.
There are things you can do to adjust your natural chronotype
While your sleep needs (when you feel alert and how much sleep your body requires) are mostly genetic, there are certain things you can do to adjust your schedule and make it a bit easier to get up or go to sleep earlier.
Our bodies respond to light, especially the powerful natural light of the sun. Being exposed to that light in the morning tells our body that it’s time to be alert and moving. At night, sitting in the dark stimulates the production of the hormone melatonin, which helps us relax and fall asleep (we mess with this process by looking at bright light from smartphones).
But we can adjust this to a degree by controlling our exposure to light. This process, called entrainment, is what our bodies have to do when we go to a different time zone – this is why we get jet lagged. But we can also use this to train our bodies to get up and go to sleep earlier by exposing ourselves to natural light in the morning and avoiding bright light at night.
This won’t turn you into a morning person, but it can make prying the covers loose just a little less painful.
Your sleep needs are personal; try to figure out what works for you
Sometimes new research will come out, and people will claim something like “studies have found that seven hours is the optimal amount of sleep – not eight.”
But as interesting as any sleep research is, different people simply have different needs. The findings of one study don’t translate into recommendations for everyone. In the case of sleep, experts recommend figuring out what works best for you.
If you can let yourself sleep naturally for a few days to a week – going to bed when you are tired and waking up whenever is natural, preferably while limiting alcohol and caffeine – you’ll have a better idea of your individual needs. During those days, try to get some sun and some exercise.
If you do all that and still have trouble sleeping, it might be time to talk to a doctor. You could be one of the large percentage of the population with undiagnosed sleep apnea, especially if you snore. Or you could have some other disorder that can be addressed.
It’s worth taking the time to figure out what you can do to sleep better, since deprivation raises some serious health concerns.